Cars Model dimension resize and wheelbase

[ZiggyM]

Hello.
After putting in the real world wheelbase, track and ride height for some cars, the tires are sticking out the sides and rubbing the front and rear fenders. I measured the models and discovered they are not scaled correctly, up to 18 inches too short in length and 3 inches too narrow in width.
Is there a way to 'easily' resize the models to their correct dimensions? Do you know how to do this and would you like to help get them scaled to their real world dimensions?

I am aware that I can use the suspension.ini [GRAPHICS_OFFSETS] section to alter the x-axis locations to give the appearance that wheels/tires are located closer to the center of the model to keep them from sticking out the sides but am not aware of a z-axis adjustment to alter the wheelbase graphically to keep the tires from rubbing the fenders.

Ideally, I would like the cars to be the correct dimensions but will settle for not having the wheels rubbing the fenders.

If you can give assistance on how to resize the models, would like to help with getting it done or know how to make the wheelbase appear shorter to fit the too short models, please let me know.

I am working on 1960s and 1970s American cars from the Trans Am, Grand American, Grand National and Winston Cup series, some of which were originally made for or have been converted from NR2003, thus, the smaller size to fit the NR2003 collision box.

Thank you for any help with this.

 

[Ruttman98]

Hello, Ziggy.

First, I am not a 3D modeler, but instead a vintage racing enthusiast. I applaud you for your efforts to bring us new cars from the golden age of racing. Just today in the "What Are You Working On?" thread, Ben O'bro offered up for development a wire mesh model of a 1969 Camaro Z/28 which could be used for SCCA Trans Am, NASCAR Grand American, USAC, late model stockers, etc.

I have been thinking about stock cars and modding for awhile. The basic bones of the American stock car were static for decades--just look at an early 1970s MPC 1/25-scale or 1980s Monogram 1/24-scale model kit and compare them to reference photos until the early 2000s. At the Des Moines Grand Prix city circuit (run between 1988 and 1992), one of the ARCA entries campaigned by Frog's Auto Salvage and skinned as a 1986 Pontiac Grand Prix 2+2 had actually begun its racing career as a Tiny Lund 1969 Ford Torino.

I do not know exactly how or if actual chassis wheelbases were adjusted when GM and Ford both downsized in 1978, but we know racecar builders are very creative in adapting to new rules. I can subjectively say that I prefer the massive mid-70s Ford Torino Elite, Thunderbird/LTD II, Mercury Montego, Chevy Monte Carlo/Buick Regal/Pontiac GP/Oldsmobile Cutlass, Dodge Charger, and AMC Matador personal luxury coupe behemoths pounding around a dusty Riverside to almost any era. (Shades of a '70s childhood.)

I recall around 1967, Ford Fairlanes were mounted on beefier Galaxie frames and items like spindles and Ford 9-in rear axles were standardized by legendary racecar builders Holman and Moody. By the late 1960s/early 1970s, most NASCAR/USAC entries were Banjo Matthews-style chassis with bodies in white supplied by the OEMs. The basic "FoMoCo" chassis formula was used by all OEM entries with a minor revision in 1981 by NASCAR establishing a 110-in WB.

Imagine the number of body silhouettes which could be brought to life with a couple of basic stock car chassis variants:

1) International Race of Champions (IROC) late 2nd and 3rd Generation Chevrolet Camaros, Dodge Daytonas and Avengers, and Gen 4 Pontiac Firebirds.

2) NASCAR Grand National / Busch Series Pontiac Ventura II/Phoenix, Oldsmobile Omega/Buick Skylark. (Ford entrants in the lower tier series were few and far between when the unusual sounds of V-6s were heard on speedway ovals).

3) One offs like Joe Ruttman's Avanti II run at the Daytona 24 Hours, a short-lived Richard Petty Dodge Magnum, Jerry Churchill's Chrysler Lebarons, and Buddy Arrington's 1981-1983 Dodge Miradas/Chrysler Cordobas and even a 1981-83 Chrysler Imperial. I love underdogs and would welcome additions to this list.

4) Innumerable local roundy-round late model stockers based on the Mopar Kit Car Chassis--a Petty Enterprises design which underpinned Dodge Aspens, Darts and Dart Sports as well as Plymouth Dusters and Volares. I would not take offense to anyone plopping a Brand X body on one of these chassis if it were a quality expendient to a properly diverse grid.

5) NASCAR Craftsman "SuperTruck" series. Back in 1994, Dodge got a tentative foot back into NASCAR with Dodge Ram pickups fielding quite competitive Magnum small block engines to challenge Chevy Silverado and Ford F-150. There was even a road race--which sometimes devolved into an off-road race--at Heartland Park Topeka.

6) Racing sanctioning bodies outside of the U.S. like the Swedish Camaro Cup, various South American stock car series, plus Aussie Fords, Chrysler, and GM Holden.

For most sim racing purposes, I would rather have a generic carbureted 366 CID V-8 and a basic chassis paired with appropriate body envelopes from the Big 3 and AMC and appropriate liveries. (Yes, if I rolled the King's 1970 Superbird at Darlington I would like to see a Mopar K-member holding up a 426 Hemi, but I would rather have something at the expense of finer details than nothing at all.) Some brilliant suspension and set up expert could tweak the basis chassis for tire stagger and offset and adjust weight distribution for dirt and paved ovals, but personally I would prefer a neutral chassis set up for road racing which usually required relocation of the fuel filler.

Dr. John Craft wrote a 1993 book called "The Anatomy and Development of the Stock Car" which I can't confirm I have in my library, but I remember as being very detailed.

Do we have a resident RD NASCAR expert who might know the ins and outs of the rulebook regarding chassis specs ca. 1967-2006?

 

[ZiggyM]

After weeks of asking around and the only answer being "learn blender", I will go against 'community standards' by sharing what I've learned instead of keeping it a secret or asking for the thread to be deleted.


Get into 'Content Manager' and open the car you want to resize in "CM Showroom".
In the box next to the window displaying the car, you should see a button under "Tools" that says, "Unpack LOD KN5". Hit that button.
This will create (and take you to) a folder named "unpacked" + the name of the unpacked car, in that car's folder and in that folder will be an "FBX" file and an "ini", along with a texture folder which holds the textures the car uses.
Get into 'Blender" and head to "File>Import FBX" and navigate to the newly created folder that holds the .FBX of the car and select it and import it.
I just want to resize the cars, not the wheels, not the tires and I've read that touching the 'dummies' is off limits so select the "STEER_HR" (in 'cockpit' in the case of the models I'm working with) and look for the 'Scale" section in one of the many blender menu that display an item's properties. (I'm sorry i can help you find which menu does what, it seems there are all kinds of menus and some display different information and what's really fun is that each time you open blender, you may or may not get the same menus).
If you've found the "Scale" information, it will show you the X, Y and Z with a "1.000" next to them. This item does not want to be rescaled so click the little "lock" button next to each axis.
Now find the "SUSP_LF" and lock it's scale. Same with "SUSP_RF", "SUSP_LR" and "SUSP_RR".
Next, find the "WHEEL_LF" and lock it's scale. Same with the "WHEEL_RF", "WHEEL_LR" and "WHEEL_RR".
At this point, I select another part of the car, the body, just so I'm not still on the "WHEEL". Not sure if it's needed but keep me from trying to rescale the wheel I just locked.
Press "a" to 'select all'. Everything should be highlighted.
Now press "s" and when you move your mouse, you should see the size changing. Look for the sizing to be shown in the upper left. Hold the 'shift" while moving the mouse for more precise control on the size. If you're like me, you'll want something like "1.0249" and will bounce between "1.0248" and "1.0250" for what seems like hours so let go of the shift, hit it again and try again. (Why there is no option to type in the size, I don't know. It could exist and I just haven't found it).
Once the size is correct, left click. Right click to cancel the resize and of course, "Ctrl+z" to undo if you miss.
You should now see your new size displayed in the "Scale" section of the properties.
Head to "File>Export>FBX". When the export window comes up, navigate to where you want to save it, give it a name and make sure to select "Apply Scalings" and "FBX Units Scale". Hit "Export FBX".
Now comes the most annoying and unreasonable part of the resizing process...
Head to "assettocorsa\sdk\editor" and open "kseditor".
Select "File>Open FBX" and select the car you resized.
At the bottom, look for the "illumination" tab. Under "Weather", go with "clear" and under "PPfx" go with "default" and now you can see the car a little better.
Head to "File>Load Persistence" and load the FBX.ini.
Most likely, the windows are opaque and if it had headlights and taillights, they aren't going to work properly. For some reason, things did not import/export correctly so you're going to have to change them and I'm not sure about all of them. I have cars that had headlights and taillights before resizing and now, they don't work.. But, I'm working on 'stock cars' that don't have headlights so it's not a big deal for me.
Head to 'Materials" at the bottom and go, one by one, through them.
When you come to 'window' or 'glass', change the Shader to "ksWindscreen".
If it's "Damaged glass", change the shader to "ksBrokenGlass".
Select the windows by right clicking on then in the picture of the car and select "Object" in the bottom left menu and change "Cast Shadow" to "False" and "Is Transparent" to "True".
Do this for all of the glass.
Once you have your glass clear, you're ready to "File>Save KN5" and get in game to see if it's working properly. Of course, you should always back up your original files before playing around with them.
Keep jumping back into ksEditor until you get all of the parts that need to be clear to be clear.
Check the forums for "clear glass in Assetto Corsa" and watch the Youtube videos I'm watching right now to figure out the rest of the process.
I've also run into a problem with chrome pieces not showing up as chrome anymore.
No clue why properties are changing so the answer to 'is there and easy way to rescale a car' is NO!
Again, maybe somebody who knows what they are doing can chime in.

Have fun!!

 

[ZiggyM]

Do we have a resident RD NASCAR expert who might know the ins and outs of the rulebook regarding chassis specs ca. 1967-2006?

I'm not an expert, I'm an amateur, but I know a bit about stock cars.. I know almost every 'stock car' mod for rFactor and AC is a Corvette on a 'stock car' looking body, especially when done by a certain type who rips people's models, sticks them on Corvette physics and calls them 'a gift to the community'... Wrong wheelbase, wrong weight, wrong track, wrong gearing, wrong everything and no aero what-so-ever.

I don't have the knowledge of how to get the data into the game. I'm still in the "WTF is 'rod_length' and why doesn't a 6.5" ride height equal a 6.5" ride height?" but I'm trying and learning by trial and error.

Ken Noffsinger's site, AeroWarriors.com, has rule books from 1960 - 1977. You can use the 'search' feature or go old style and see the directory - https://aerowarriors.com/rules/nosearch/

The 1964 rule book is missing but he sent it to me years ago so it's in my spreadsheet along with the rest.

The "Chrysler Document Archive" is another source I've used for decades (https://aerowarriors.com/cda.html). It's got wind tunnel testing, on track testing, setup sheets, torque curves, HP, HP loss, shocks, springs and all kinds of specifics I've put into my spreadsheets over the years.

I asked modelers for help and get 'learn blender' and I ask for physics help and get "You'll figure it out". LOL

I've got tons of data.. It's trying to figure out how to get it into the game that's annoying. If anybody reading this is interested in helping out, let me know!

Have fun!

 

[Kukoo]

The reason lights don't usually work is that the object names get changed, usually like for example LIGHT_FRONT_POS00 wil get renamed to LIGHT_FRONT_POS00_65vertices etc, as ac uses object names for lights these have to match what is is in the lights.ini. These names can be checked in acm (right click on lights in showroom) and it's far easier just to change the names in the .ini file - just copy n paste, than to rename them back on the model.

When unpacking the model, before using Blender (or whatever else) import the fbx into kseditor and save the persistance file (no point exporting the kn5 tho). Make your changes in Blender and when your done import into kseditor and load your original persistance file - this may help as I think transparencies get lost when the .fbx is edited elsewhere. As well as this you have object transparency as well as material transparency..something that caused me a bit of confusion at first and you can toggle this in acm showroom but its better to sort this out in the editor and save a persistance.

 

[ZiggyM]

The reason lights don't usually work is that the object names get changed, usually like for example LIGHT_FRONT_POS00 wil get renamed to LIGHT_FRONT_POS00_65vertices etc

Exactly what happened. It has changed to some "ce63700ab" from '1206' or similar. I tried saving the persistence from the original and loading it back in but still lost a lot so I spent the rest of the night with the original in one window, the rescaled in the other, going object by object, material by material. And it looks really good now!

Thanks for the help!