Common Issues With Vehicle Mods and Their Solutions

Detailed information on the purpose of LOD and on how to create them can be found in the guide LOD Models.
The following list gives rough values of our recommendations for the polygon count of a car with a medium to high detail level:

• L0: ~ 50,000 - 150,000
• L1: ~ 20,000 - 40,000
• L2: ~ 10,000 - 15,000
• L3: ~ 5,000 - 10,000
• L4: ~ 500 - 1,000

These numbers are based on default vehicles, in particular recent DLC vehicles, which are higher poly than older models. Exceeding these recommendations can lead to performance issues.

This is caused by strong differences between the LOD models. This can be either a problem with the car's mesh, such as parts missing from an LOD, or with materials, such as parts suddenly changing color or reflection. It can also be caused by having LODs with a very different polygon count, causing a noticeable switch to the low detail model.

To solve it, make sure the same materials are used for all LODs, that all parts include LOD models and that there are no big differences of the geometry of one LOD model compared to the next one.

Some object IDs may not be included with ZModeler by default or they may be bugged, download the gta_parts.xml at the bottom of this post to reset the IDs.

The chassis duplicating itself when a part such as a door, a bumper or the hood falls off or the car explodes is caused by an incorrect hierachy. Make sure you don't have multiple objects with the same name. Stick to the name of the parts of default cars, use misc_x (x being any letter) for additional parts. It may also be caused by an incorrect gta_parts.xml in ZModeler, if the hierachy is correct and the issue happens anyway, try using the gta_parts.xml at the bottom of this post.

Make sure all collisions are set up properly, that both the glass material and the object have the "Crash" property, and that the window has at least an L0 and L1.

A detailed guide can be found here: Troubleshooting Glass Collisions

Make sure all collisions are set up properly and that the object has at least an L0 and L1.

One of the vehicles collisions is not set up properly. All collisions require a collision ID and the "deformable" vertices property to be set.

This is caused by normals. They are used to set the direction of the reflection at each vertex. ZModeler has a calculate normals tool that can be applied to whole parts or specific vertices. To keep desired edges, detach the affected part before calculating.

A detailed guide on calculating normals in ZModeler can be found here: Calculating normals

For many complex models, different normal calculation tools outside of ZModeler are used. In this case, calculating or smoothing normals will break properly set up normals.

When an object underneath glass isn't visible through the glass but is visible from the inside or when the glass is broken, the material order is most likely incorrect. Glass materials need to be loaded after materials used in the interior and can be sorted using drag and drop in the Material Editor.

To prevent glass from getting tinted, paint the Alpha channel black. Make sure the Primary color option in the properties of the object is on. More information on tint.

For the badges shader, the vertex paint alpha channel is used for transparency. Paint it fully white for full opacity.

This can be caused by different problems:

- In many cases, more textures than actually required by the model are included. Additionally, all vehshare textures are loaded from seperate .ytd files and are not meant to be included in a car's .ytd.

- The textures included have very high resolutions. No texture should be larger than 2048x2048, 4k skins should only be included in the hi.ytd version.

- Textures are not compressed properly. For almost all cases, DXT compression is recommended. More information can be found in the guides Texture Compression and Mipmaps.

When a car needs too much video memory, the game will not be able to load all textures. Buildings or streets might use very low quality textures or disappear completely. In most cases, this is caused by having too many high resolution textures. The game is for example not able to handle many 4k liveries, it is recommended to include no more than 4 in the ytd file.