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Mission8: Trials and tribulations of racing BMW's latest GTE

On September 2017 the BMW M8GTE made its first public appearance at the Frankfurt Autoshow.
Set to compete in both the 2018 FIA World Endurance Championship and the IMSA WeatherTech SportsCar Championship,
it also marked BMW's return to Le Mans with its first factory-backed car since 2011.


2017-pres-frankfurt.jpg

Talking shop
Press releases were full of the usual corporate shop talk, how the new M8 would be sporting a 4.0-liter twin-turbo V8,
make about 500 horsepower and would incorporated BMW's latest cutting edge technology, aerodynamics, laser lights
...bla, bla, bla....

Clearly the Munich brand was grabbing the opportunity to use the GTE as a marketing tool for its M8 coupe road car.
The street legal version of the M8 GTE not due to make its first appearance until may 2018.

I could not have cared less, chances are I'll never be able to own a M8, let alone race one in the flesh.
The moment I saw the first images of the GTE, I stopped reading...cause all I could think of was:
"How was I going to get my hands on that car.... and race it at Le Mans...1/32nd"

M8GTE-wip01.png


Time Flies when you're having fun
Since then two years have past, time sure flies when your having fun. A lot has happened in between, the M8 has won the Daytona 24hrs...
...and has been canned in the WEC. I waited almost a year for one of the major manufacturers to do this car...never happened.
So exactly one year ago I decided not to wait any longer, and started my own Mission8.

In this topic I will post the trails and tribulations I've come through on my Mission8. As I write this the project is already starting its second year...
So before I start posting...I already have a load of backlogged posts :bigsmile:

From a unique scratch build one off...to a limited production kit
But before I turn the clock back to 2018, here's an image of how far the project has advanced so far.
I took this image a week ago, it shows the 3D printed body that will be used as a master for the GRP laminated body...
...or actually bodies.
Because as the initial Mission Goal is now within reach, I have decided to extend the mission objective.
In the last 6 month I've been working closely with SV Workz on other projects . As a result of this close cooperation we've decided to do a limited edition run of mission8 kits.
Meaning that after I've run the car at the 1/32nd 2020 Le Mans 24hrs... you could race this car too.

To be continued:
mission8-SV-presentation01.png


With kind regards
Tamar
 

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Looking forward to seeing the real thing at Laguna Seca -- (and tomorrow via the telly at VIR) but would dearly love to have one of the kits when they become available!!! Thanks for the update!
 

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Discussion Starter · #4 ·
Good evening Slotfriends.
Today we're 4 weeks away from travelling to Leamington Spa for the 9th Edition of the Disca Le Mans 24hrs....and it has been more than six months since my last "confession".
Time for an update on my
Mission8 also know to insiders as "Mission wait"

Because for many months after posting the first publication photo's of the 3D printed master...al I managed to do was cut and test fit one master for the right hand headlight lens and one for
right hand the tail light lens...not much to write a progress report on.

SV8GTE-wip02.png


M8 waiting game
At first the M8 was intended to make its debut at the DiSCA finals in Barcelona on Nov 4th, remember I posted those publication shots in August 2019...so plenty of time right?.
Well I got a bit more involved into the organizational work for that final than was provisioned ......so....not enough time to finish the BMW....raced the Ford GTE...again...
...and plenty of time till the next event in Januari right?
So November flew by, but by half December Stefan Nalbach (Prospeed) send me the first renders of the Hybrid M8/M6 3d design.
The M8 Mk1 chassis was a hybrid version that allowed us to run and test the M8 Chassis under the M6 GTE we raced last year at Suzuka.
As you can see its got the M8 diffuser attached to the motorpod . The same way as first used on the Ford GT.
SV8GTE-wip03_chassisMk1.png


Got the chassis printed in time for the dec 15 test we had @ the Suzuka track, December is always busy work wise but with a last minute push we managed to get the Hybrid M6/M8 chassis assembled and up and running under the "old" GRP M6 body.
I had also modified the original M6 chassis mounting the diffuser to the NSR SW pod "Ford Style"
The new Prospeed M6/M8 chassis is similar to the one Prospeed used for their C7R corvette they raced at LM 2019.
It has a Prospeed shortcan motorpod with a 10˚AW/SW configuration and 1,0 mm offset. Attached to the rear the "now correctly sized" M8 rear diffuser.
Had to shave 0,1 mm off the bottom of the strakes as they touched the track on the first roll out (later I found out that I had not tightened the diffuser screws completely)
Must interesting was how the Hybrid chassis with its narrower and more forward position of the side suspension compared the old NSR podded M6 chassis.
SV8GTE-wip04_chassisMk1.jpeg


The first test went very well, the new chassis was still a bit slower, but showed promise. I'd figured that we needed a bigger offset pod to get it on par with the Ford, had a quick chat with Stefan Nalbach who immidiately made one and had it printed asap by Shapeways. It arrived just in time to be assembled and run in the last test sunday before the Suzuka 6hrs on Jan 20...
But there things took a bit of a downfall.

With the new Motorpod the M6 ran well, nice and smooth...but when we checked the times was 3-4ths slower than the Ford.😳
And when we start pushing to match the Ford's times the BMW became very unpredictable 😬
We switch back to the "old" prototype M6 chassis..and same thing. 3-4ths slower than the Ford and unpredictable when pushed hard.
We tried several different set-up changes to make the M6/M8 behave...but it would'nt...and then we ran out of time.

With still a ton of organisation work to do in the week till the race and with no gauarantee we would manage to solve the problem during saturday's free practice.
...we decided to not run the M6/M8 and race the Ford instead....again.

A good call as it turned out the weekend after. First of all with the more stable Ford even though I was waisted as usual we did manage to take 2nd place overall and win our GT class.
But by just one lap difference from the second placed GT car: the Prospeed Corvette C7R.

By now it was Jan 31st which was the cut off day, last day, according to DiSCA rules, to pay the remaining enry fee and make changes to your car choice for the LM 24hr race.
And although I had an idea on how to fix the problem with the BMW chassis....we decided to go for the plan B and switch back to the Ford GT. Better safe than sorry.

To be continued

With kind regards
Tamar
 

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Discussion Starter · #5 ·
Dinnertime meant I had to cut off writing, also made for a nice cliff hanger
wink.png

Because I would not be posting here if there wasn't more to the story than just another race cancellation for the M8

Weight off my shoulders
Because with making that difficult call to switch to Ford for the DiSCA LM24hrs....it was like a heavy weight was lifted of my shoulders.
And as it happened, I also had some free time on my hands in the past weeks.
Time I did manage to spend on the M8, finishing the master casting the silicone mould and laminating the first body..
...so that last weekend we had our first roll out @ Suzuka.
Finally after a year an a half, there is a 1/32nd M8 GTE.

SV8GTE-wip05_rollout.png


To be continued

With kind regards
Tamar
 

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Hello Woodslot, and all other slot friends. As you may have noticed the posts in this thread are jumping up and down the sequential timeline of the GTE build.
Its a bit like watching a TV series that starts near the end of the story and then tries to explain to you how they got there via lots of confusing Flashbacks
wink.png

So tonight's episode will grab your attention, its like an end of season cliffhanger, one that ends with a Big Bang
wink.png


A Penultimate Test
In the last episode we had the roll-out of the car in "naked" GRP. As a function test it performed well, we identified some handling problems and other issues like a bend chassis. (on which I will post later).
Spend most of my free time last week addressing them because this Sunday we had an other test day ion Best.
Based on the results of Sunday's test we would make the final decision on if there might still be a chance to run the M8 at Le Mans.
So by Sunday afternoon I placed the M8 on the track, her body now dressed in a nice clean and white test livery, her chassis straightened and reinforced.

Pre_crash-test.png

The SV8GTE all dressed up for her penultimate test.

I even managed to install the headlights properly, added the head and taillight lenses and mounted the flexible rubber Wing supports...cause I needed to know, would they stay on the car or come off during running...or crashing.
By the way, that's the Prospeed Corvette C7R flashing by in the background. They to were shaking down their Le Mans cars, so both teams could compare where they were at..with the competition
wink.png

First laps with the M8 showed that the car was now stable and predictable. No more bottomming out on the high parts of the track, initial lapttimes were in the low 12's.
Lennard did some consecutive runs with both the M8 and the Ford which showed that the track was a bit slower than last time.
The Ford also had problems getting below the 12 seconds but did manage an 11,96. Prospeed C7R's average times were in the mid 12's with a best of 12.09.

We then started to fine tune the set-up of the M8, mainly playing with the front pod screw and minor adjustments to the diffuser grubscrews.
Slowly, but steadilly the laptimes on the M8 went down. Lennard setting an 11.93 as best M8 lap of the day.

SV8GTE-test-run_0803.jpg

The SV8GTE, Ford GT LM and the ProSpeed C7R coming out of the 130R

With me and Steven being able to do low 12's and Lennard dipping into the 11's frequently we were pretty pleased with the M8...until it started to become a bit unstable again.
Upon inspection of the car we noticed that both front bodyscrewpost had sheered of in the body.
I sort of expected that this would/could happen as I had glued these into the body "rigidly" with cyanoacrylic glue (superglue) with a flexible glue on top.
The previous bodyposts I had glued completely with "flexible" Bison Tix or Bison Max repair.
What was unexpected was the apparent minor crash and force needed to break the bond of the Superglue, but on close inspection I noticed that the glue was still in place.
The post had seperated from the body by taking one layer of lamination with them.
SV8GTE-wip06_front-bodyposts_repaired.pn

The SV8GTE after I had reglued the most forward body screw posts with flexible glue (Bison Extreme repair) more on this in a later post.

Taking Stock, decision time.
With Steven and Lennard needing to leave, we took stock of the M8 situation and determined that we all would prefer to run the M8 instead of the Ford....
...That handling and speed wise they were alsmost on par and that with some more testing and development the M8 has the potential to become even better.
But given the uncertencies of the body posts, the fact that we would not have the first true 3DP race chassis from Shapeways before end of next week, which would require at least an other weekend of testing...
...and that we would still need to do the second body (lamination, paint and lights) ...with just 3 weekends till showtime...

We decided that it would be best to continue with the Ford and develop the M8 in the next race (most likely Rockingham this summer).
But....as this was supposed to be an M8 test, we did not leave it at that.

With the glue set enough to remove the body screws, we did another run with the M8 with the bodyscrews back in the original Carrera position (so glad I had left them in place in the body) to see if the car would be slower.
It was, by a tiny bit. Lennard now managing "just" a 11.96
End of the day, Lennard and Steven had left. I had one heavy last test to perform. I knew I had to do it, but kept postponing te inevitable...good thing I did.

I had noticed that the glue on the most frontal bodyposts had set...enough to re-mount the body on them and tighten the screws.
I then fiddled a bit more with the suspension travel, chassis float and increased the amount of pressure by which the body was leaning on the rear diffuser.
As I did this my laptimes with the M8 came down from the low 12.20's to low 12's and posted a best lap time of 11.96... and I'm usually at least 1 -2 tenths slower than Lennard.

So time for the last scene of this season finale

Crash test Dummies
When you're building a slot car with a laminated GRP body that you want to race in the DiSCA Le Mans 24hrs, the most tasking, demanding 1/32 digital endurance race in the world...
...How can you find out if its strong enough to survive a head on crash at full speed on the 16m long Mulsanne straight?
Because these things can or beter will happen.

Well...you do a crash test...as this kind of knowledge...can only be acquired... the hard way!


SV8GTE-crashtest2.png
[/size]

Location: End of the Pit straight (6m long) 1/32nd Suzuka track, Src Eindhoven, Best, The Netherlands.
Test subject: 1/32nd SV8GTE GRP body 22 gr, total weight 76,2 gr
Crash test dummy: Our Scalex Nissan GTR "Safetycar", Injection moulded plastic body 35 gr, total weight 86gr


Here's the link to the you tube play list: SV8GTE Crash Testing
Note: Not for the fainthearted, no other slot cars besides the SV8GTE were hurt in these videos

to be continued.....

With kind regards
Tamar
 

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Dear Matt, can always rely on you for a nice bit of light banter, don't worry even without the M8 and having two near ready to run Fords....I'll always find some thing to install, decal or add right before the start.
But ok back to today's episode, wow almost 200 views for the Crash test videos....time for a damage report.

Crash test Dummies, post test analisys
So those who watched the videos will have noticed that the first time I ran into the Nissan.... I chickened out.
As we checked the videos I noticed the head lights going out just before I hit the Nissan. Ok I had spent countless hours on getting the M8 test car "just right", the spirit was strong but the body was weak..
At the last moment... my finger had come off the throttle.
Still a pretty good hit, but with no damage to the M8...I had to do it again, no place for the faint hearted.
In the 2nd test I did keep the pedal down (trigger pressed) and hit the Nissan at high speed and with full force, a clear hit..with a damaged nose, a split splitter and paint chips flying off. (just love that slow-mo)
But besides a bit less ground clearance due to the damaged front Splitter...the car was still very much drivable.
SV8GTE-crashtest3.png


Back home I did some more damage assesment. Frontsplitter itself had remained intact (carbon/kevlar laminated) but bend downwards with such a force that it tore the kevlar reinforcement in the centre of the grill clean out of the resin.

The blow delaminated the gel coat (that's the first thin "cosmetic" layer of resin) of the grill from the (thin GRP) lamination behind it and caused the right side to tear.

SV8GTE-crashtest5.png


Back home I peeled the broken the gel coat from the grille and saw that the GRP had teared as well.
he tear continues up and to the right (viewers left) where the paint chipped off, and then up straight ending in the hood just above the right headlight.
That area I had dremelled a bit to thin to remove the excess resin from the lamination process.

SV8GTE-crashtest4.png

Pictured above, you can see how far the nose flexed during the crash by the traces off chipped paint.
Such was the force of the blow and it travelled that far aft, that a bit of gell coat chipped of the lamination behind the leftside wheelarch. (picture above right)

But, the reglued front body posts to wich I had mounted the chassis...were still firmly fixed in place !!!
So definitely going for the flexible glue. And last but not least the structural integrity of the lamination was still intact on the inside of the body.
SV8GTE-crashtest6.png


Crash test Dummies, post test evaluation: Good and bad news
I've never crashed a car like this...deliberately, but I'm glad I did it now, that I had the luxery to do it now. Because crashes like this will happen during the 24hrs.
And the speeds and forces of a hit on the 20m long 1/32 Mulsanne are a lot bigger than on the 6m Suzuka pit straight.
So the good news is that although its bad news to the way the M8 looks....it just that, cosmetic damage which could have been easilly repaired.
The lessons I can draw from this crash test will allow me to improve the lamination process in such a way that this will not happen again...during a next crash test.
The bad news is, to be sure that I have succeeded I will have to crash it again
lmfao.gif


to be continued

with kind regards
Tamar
 

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Discussion Starter · #10 ·
From beginning of December till now, feels like one long turbulent flight. Trying to get the M8 ready for the Suzuka 6hrs and the 9th edition of the DiSCA LM 24hrs.
The lull I'm in now after it has been cancelled feels like the eye of the storm as most of Europe braces itself against the full force of an ill wind.
With no racing planned for the near future...perfect time for an M8 GTE Flashback. Dail back the clock to 2018.


In the beginning....
After waiting for a year, none of the mainstream manufacturers had even mentioned plans to start working on a M8 GTE. So like 4 years earlier with the Toyota TS 040...
...I decided to make my own. And this time I really had to start from scratch, as unlike with the Toyota there were also no other static scale models available of the car.
In August I discussed the project with my good friend Fola (slotfabrik). Would he be interested in a joint venture where he would do a 1/24 version and I would do the 1/32nd scaled car?
Although we're both done our fair share of manual masters we decided the first thing to do was to search for a designer that would/could do a 3d Model for us...

...because at that time ...2d, let alone 3d...there was nothing.

SV8GTE_selecting-artists.png

3D Renders of the same BMW M6 GT3, done by 4 different 3D artists....will give you 4 different interpretations of the same car...spot the differences, which one to choose

There were plenty of 3D artist to be found via the web, some of them "specialized" Automotive modellers, but after a lot of browsing Fola and I only considered a few that we both agreed on as really good.
Because, unless one has the original files from the manufacturer, 3D modeling, like classic sculpture, is really a fine art.
Check the 3D Renders in the picture above. All of the same BMW M6 GT3, done by 4 different 3D artists....which will give you 4 different interpretations of the same car...

all of them good...hard to spot the differences, which one to choose?
In the end we found an artist that did freelance work for the (automotive) game industry. His portfolio contained the most accurate and detailed 3D model of the BMW M6 GT-LM.

We contacted him and he was up for it, so I provided the artist with all the reference photos and research I had collected over the year.
I left it to Fola to make a deal (he's much more a business man than I am). For a fair amount of money we would get our 3D model, but no in between work in progress updates.
No unique use of the model let alone unique rights. Deadline would be October 2018, payed half up front and half upon delivery.

And then there was...light
Oct 2 was the promised delivery date for the 3d model and behold that morning Fola got the first renders of the M8GTE. I must say..I was most pleasantly surprised.
Because in the previous weeks the project had been a giant leap of faith, had we picked the right guy, how accurate would the model turn out to be?
As the renders lit up my screen, all my concerns faded away. Proportions were good, the amount of detail immaculate, he'd done a very good job, the work of a true artist.
There were a few small details that need to be finished (mirrors and dashboard) which he promised to do that week. So by mid October we had "our" 3d model, all we had to do now was make it printable.

SV8GTE_first-renders.png


to be continued

With kind regards
Tamar
 

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Jesus Tamar you cannot start a post like that and leave in the middle of it...anyway, can you pass the 3d model to Slot.it to do a mass production injected mold for this nice car?

By the way, Area71 is offering both 1/24 and 1/32 options of the M8. But I am sure you are aware of this already.
 

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Good evening Gio, my late midnight post... your morning/afternoon news ?
happy.png


Well yes I can, just did, about time I told the whole story....from the beginning.
And yes, compared to 2018, (3D) models of the BMW M8 can now be found left right and center.
Picked this one up from China last Christmas for just 17 bucks incl postage (1/32nd static pullback motor)
As you can see advertised scale accuracy not completely "by the book", same goes for the reputation of Chinese toy makers on respecting OEM Licenses.

Different story for Slot.it, even if they could, not sure they would, venture into commercially producing a contemporary Beemer.
Bavarian lawyers monitor everything on the web, threatning even the smallest makers with law suits and sanctions. And with succes ...
...try searching Shapeways 3D shops for anything BMW related...you'll come up empty.

Which is also the reason why I've started to post and refer to my "own" creation as a SV8GTE
innocent.gif


SV8GTE_chinese_toy.png

On top the 1/32nd SV8GTE "post crash test", below the 1/32nd (more 1/35) scaled Chinese Die cast. Scale accuracy not the greatest asset of the latter, but in a crash test...I know who would come out on top.

But as we Dutch say: "Je weet maar nooit hoe een koe een haas vangt". (You never know, a cow might catch a hare)
Current cooperation between Sv Works and Slot.it (Oreca 07) proof that although highly unlikely, such things occasionally do happen.
And don't worry, after a few more flashbacks, I'll get itchy fingers and start working on the car again posting more updates with...

to be continued:

with kind regards
Tamar
 

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3D printing: skins vs bodies, meshes vs solids, squares vs triangles...Babylon rules
Oct 2018, on my hard disk most likely the most detailed 3D model of a BMW M8 GTE, as an extra the 3D Artist had thrown in a perfectly detailed interior.
So what now...press "CTRL P" for print? Well I knew it was not going to be that easy, Fola had done projects like this before.
We knew that we would need another 3d specialist to convert the model into a 3d printable file. But boy was I in for a steep learning curve.
Some of the members on SF are working with 3D designs and prints, but for those of you that have no experience at all...a short "simplified" introduction.
A kind of summary of the stuff I was about to learn the hard way,


A small introduction into the world of 3DP
If you want to create a digital 3D model there are basically two methods, two ways of doing this, you can work with skins and/or with bodies.
Working with Skins is best illustrated by thinking how, in the old days, a carrossier would use sheet metal to build up the outer skin of a car body.
For working with Bodies you could best think of a scratch builder, carving that same shape out of a solid block of balsa wood.

SV8GTE_skins-vs-bodies.png

On the left: Aluminum skin shaped on a wooden buck to form the body of Daytona Coupe. On the right solid blocks of Jelutong wood to be cut back to form the body of a Tojeiro Climax GT

Meshes vs Solids
Skins are often referred to as meshes, like a wireframe, but unlike the metal skin of the Daytona Coupe they don't have any physical properties, no thickness.
They are but digital boundaries. For example to create a cube you need to mesh the 6 faces of that form a cube, the shape of the cube would be defined, but not its contents.
If you want to 3D print that "meshed" cube you need to convert the mesh into a Body, often referred to as a solid, because...well that's what they are after conversion.... solid.
In general "free form" 3d modeling like for Film, Animation and 3D Games use meshes, 3D modeling for fabrication of physical parts prefers working with solids.

Quads vs Triangles
So you would think that each 3d software program would have a simple drop down menu with a function "convert mesh into a solid". Well yes and no.
First of all there are many 3D software programs and again there's a two way division in how they construct a mesh... quads or triangles.
In general they're split along the same lines: Film, Animation and 3D Games use quads, Cad cam and 3D printers use triangles.
Quad meshes are better for "optical use" as they provide better and smoother renders, but they require more computing time and data.
Triangle meshes require less computing power

SV8GTE-tri-vs-quad.png

On the left: the original M8 GTE 3d model, as you can see the mesh is build up by squares (quads) . On the right an example on how quad mesh "renders" better than triangles.

Babylon rules
As you've probably guessed by now...that wonderfully detailed 3d model we got...had a quad mesh needing to be converted into a triangulated mesh before converting it into a printable solid body.
Like most computer programs destined to do the same work..they don't really like to talk to each other. Unless you have someone that really knows how to convert the one into the other...a lot of the data will one lost in translation and...Babylon rules
But as I mentioned earlier, Fola had done these projects before, he had a guy that could do these conversions for us. So we send him the file and he said he would dig into it.
In for another waiting game, in the mean while I returned my focus to the BMW M6 that we'd been using as a test hack for the development of the M8 Chassis.

to be continued

With kind regards
Tamar
 

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I have run into the same sort of issues that you mention above Tamar. I work with 3D CAD, so I can design my own things (chassis), which triangulates surfaces, but it is no good for dealing with other people's surfaced models (bodies).
Sigh, trials and tribulations of the modern world!
 

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Hello Shaynus
Being able to lear new stuff with each project is what's kept me in this hobby for so long. In the past 4 years I have made various attempts to have a go at 3D modeling.
By now I do understand the basic requirements and tools available in 3D modeling and its many software platforms.
As with all other things, becoming proficient in 3D modeling requires a lot of practice, you need to reprogram yourself on almost a day to day basis.
And even though an old dog can learn new tricks... it just seems to take forever...and I don't have the patience to get my 3D skills up to the level needed for these projects.

But by combining my 25 years of analog building experience with my limited 3D skills I now to manage inspire and guide a group of younger 3D guys to get the projects to a level I think they should have.

With kind regards
Tamar
 

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Discussion Starter · #17 ·
Hello Shaynus...you're up late
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As my "paid" work requires a Mac OSX, most of the Software I tried to master needed to be on that OS. Not really keen on running Windows on my Mac.
So far I had a go at Sketch-up (pro), Blender and Fusion. For working with Meshes and Solids, Fusion is i.m.o. the best option it combines parametric workflow with some pretty good "free modeling" techniques.

Downside of Fusion is that due to its "cloud based" nature it can get very slow when working on complicated models.
But as I mentioned before, I'm not the one doing the 3d modeling work right now, I just use the extended features of Photoshop and Adobe acrobat to inspect the files that the 3D guys in the team generate.
They mostly work with Solidworks and 3DS max.

With kind regards
Tamar
 

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Discussion Starter · #18 ·
True Scale: To be or not to be, that is the question
Slowly working through my back log of M6 and M8 post, some recently posted pictures of the Sideways BMW M6 GT3 motivated me to write about this topic now.
First of all let me state that I.m.o "True Scale" is an ideal, and as with most ideals, in reality nearly impossible to achieve...translated to 1/32 slot cars...make that impossible.
Because if one was to truly scale down a 1/1 car a large number of parts would become too small or thin to fabricate, manufacture, let alone use as parts for a slot car.
So for me True Scale (or true to scale) is more about how well a 1/32nd or 1/24 model captures/represents the
proportions of the actual car.

"Artistic Liberty" vs "Slottification"

As I mentioned in my previous post, modeling is an art form, as such there's a bit of "artistic" liberty in each model, a necessity for those areas that will become too small when scaled down 100%.
Every model manufacturer (static or not) has its own signature when using such artistic license, Tamiya modelers like to beef up certain proportions more than their colleagues at Fuji and Hasegawa.
Studio 27 can at times be more "square headed" than lets say Hiro models. Carrera dimensions tend to be more "Teutonic" than Scalex "Imperial Scale" (Scalex usually the most scale accurate).
Most of the Spanish and Italian manufacturers following that same British tradition, maybe some slight slot 'optimization' here and there or as I like to call it "slottification".
The most renowned example of such "slottification" the NSR Mosler. Anyone that has seen the difference between a Ninco Mosler and the slottified NSR will know what I mean.

SV8GTE-truescale01.png


Now most of us slot pundits will always have to accept whatever amount of "Slottification" the manufacturers have applied to their RTR cars. Which brings us back to my story...
... as one of the reasons why the M8 GTE model was so incredibly detailled..was because the 3D Artist had drawn it scale 1/1.
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As you can see in the screenshot above its digital footprint measured 562,85 cm x 247,37 cm which was a bit odd as when checked against my reference data that was way too wide and too tall.
Ok so sometimes the published car specs you can find on the web are a bit off, and unless you have the chance to measure the real car there is no way of verifying them...but the M8 was half a meter off?!?

True Scale, horses for courses and X-Y-Z axis
Back to the timeline, by now it was mid November 2018, we'd just lost 4 weeks as we needed to look for a new 3D "translator", Fola's guy had returned the job...too complicated.
Via the web I got into contact with a young Slovakian 3D student, another leap of faith needed here, but as it turned out Villiam (Vilo for his friends) was the perfect guy for the job.
We both agreed that this project would be one were we would go through a steep learning curve as this conversion would be a first...for both of us.
We knew we would make mistakes, learn stuff the hard way, trail & error or as we Dutch say "met vallen en opstaan".

In fact I made a mistake with the first step in the process, rescaling the 1/1 3D model to 1/32. The calculated Scale dimensions of the M8 would be 155,3 x 63,9 x 37,88 mm, wheelbase 90,0mm.
I knew that the dimensions of the M8 model were a bit off. For the length that could be explained by the overhang of the front splitter and the rear wing sticking out the back.
The difference in height could be explained by 1/1 car dimensions measured while standing on its wheels (which our model had not) , but I had no reference by which margin.
The width, even though this was also off, still looked like the most reliable dimension, so I told Vilo to (re) scale the whole model down to 64,0mm wide.
But when we checked the 3D model of the body against the 3d model of the M6 Chassis that Stefan Nalbach had designed...the wheelbase was way shorter than the 0,6mm it should have been.

We checked what the width would be with the correct wheelbase, 67,2mm, way to wide, even if you would account for the 3mm tolerance of the DISCA Le Mans rulebook.
So what had gone wrong? Silly stupid mistake actually... had told Vilo to rescale the "whole" model down to 64mm wide...
... had not noticed that the original 3d model and Vilo's rescaled model also included the wing mirrors sticking way outside the body.
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Our first "Babylon rules" moment, just one single word lost in translation had totally screwed up the correct dimensions.

SV8GTE-truescale02.png

We had a laugh and Vilo rescaled the body again, measuring the max the width of the body over the widest point of the rear wheel arches... et voila @ 103% we got the correct wheelbase and width.
But mounted over the 3D mock up of the chassis something still looked a bit off. First of all the chassis was sticking out underneath the body, and although at the correct wheelbase...
...the way the wheels sat in the wheel arches was not to my liking. Looked like we needed to mount the body lower on the chassis.
But when I overlayed one of my 2d blueprints I noticed that the roofline was already a tiny bit lower than the 3D model and that 1/32 20,5mmø slotrace wheels are not even close to true scale.

SV8GTE-truescale02a.png


Ok a little bit lower roofline...I could live with that, but the vertical alignment of the (too small) wheels in the arches...no. If we lowered to body @ 103% to center them, the body would rub the track.
If we enlarged the body by 105%, the body would be wider (65,5mm well within the 3mm DiSCA tolerance) but it would also be longer, bigger.. and we would need to adapt the chassis wheelbase.
But one of the advantages of 3D modeling is that you can modify the X,Y,Z axes (LxWxH) independently.

So we fiddled around with percentages and arrived at the following "slottificational" compromise: Length and width (X,Y) at 103% which gave correct 90 mm wheelbase and 64mm width.
No point at having a 65,5 wide body with the DiSCA max allowed track width at "just" 63mm, this would only make the car look stupid with the wheels tucked 1mm deep inside the body.
No point at making the body longer or increase the wheelbase, at 90mm it was close enough to the 92mm of the LMP's, longer would also mean heavier.
We did increase the Z axis to 105%, as you can see in the image below, with the increased height the wheels were now centered in the arches, roof height an good match with the blueprint,
and the bottom of the body flush with the chassis.

SV8GTE-truescale02b.png


Nothing we could do about the "undersized" Slotrace wheel diameter, DiSCA handout slot.it N18 and F22 tires just don't come bigger than 20,5mmø.
But the difference is less noticeable here as slot cars also run @ much lower ground clearance than their 1/1 counterparts.
So with the "Slottification" of the SV8 GTE dimensions set, Vilo commenced to translate the Mesh Model into something printable in true scale
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to be continued

With kind regards
Tamar
 
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