[Tamar]

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.


 
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.  
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. 
Our first "Babylon rules" moment, just one single word lost in translation had totally screwed up the correct dimensions. 
 


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.
 

 
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.



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  

to be continued

With kind regards
Tamar