Hi,

My goal is to replace maxis police car with another model. At this point I have converted model for buyable object and when this is ready I'll replace the model. However, when picking the vehicle from catalog and placing on pathway the game crashes.

- The vehicle is self made recolor of TreZillah Saab900.
- I made and added sirens on roof and added imported the models to GMDC. I have UVmapped and textured this new model.
- When I previewed the model in cGeometryDataContainer the car appears textured but sirens are dull grey.
- Textured object works nicely in game, but sirens are missing.
- I googled the problem and found some old tutorial from russian simmer (from 2005 or something), where she explained same problem with a sofa she was working on. The legs of sofa where missing ingame, as "the texture is not linked to model" or something. Sadly I have lost the tutorial and cannot link it.
- I followed the tutorial, managed to do required steps at SHPE, GMDC and TXMT and finally as previewed from cGeometryDataContainer the textured works fine.
- I opened game and when the car is picked from catalog it appears as it should. However, when placing the object on pathway the game crashes.

I read somewhere that crashing may happend due to duplicate GUID. The object is made from original car file (I have also tested cloned one) and original file or copies or its recolors are not in download folder. I have also tried giving object new GUID and having both original and cloned files ingame (they both appear in catalog fine). But crashing always happens when placing it. I have ran GUID scanner in SimPE and the package appears as duplicate GUID (no matter what GUID I give it). Before linking the textures, same file were not marked as duplicate GUID.

Any idea?

- Dull grey items in an object usually means something is wrong in the materials or the resources that have subset names (TXMT, TXTR, MMAT, SHPE, GMND, GMDC). Make sure subset names and texture names match up everywhere.
Here's one tutorial on adding subsets: https://modthesims.info/t/103379
And an addon: https://hugelunatic.com/adding-recorable-subsets/
And how to fix them: https://hugelunatic.com/making-objects-recolorable/

- Cars are animated, so make sure you've used the proper method to change the mesh, and that you've preserved the skeleton and joint assignments. If you add anything to the car, you will need to add this to the joint assignments for it to follow the car.
(I think there was a tutorial spesifically for cars around, but can't find it - this one shows the process, though: https://modthesims.info/t/433766 )

- Usable cars have multiple GUIDs/OBJDs. Make sure you give a new GUID number to each OBJD, or the vehicle won't work (the main GUID box, don't touch any of the ones below the tick box that says "change MMAT").

- For the main GUID/OBJD in an object (and only that one), you need to either tick the MMAT box or copy the new GUID number to the MMAT, so the object can be recolored.

- If you recolor the item by editing the existing file, it may not be fully compatible with the original item, even if you give it new GUIDs. They may show up, but there could be some issues between them. Usually you'd need to do at least one more step to make the item fully standalone (fix integrity, possibly with slight name change).