Hi, sorry for the delay. Next time, in such cases, I would highly advise contacting us at
https://corona-renderer.com/link/contact-supportI have some further questions about this:
1. Is the original car model made of separate objects or is it a single mesh with multiple elements?
2. Which exact version of Corona and 3ds Max are you using?
3. Can you list simple steps how to reproduce this issue with some simple geometry like boxes?
I _think_ what happens here is:
- your original car is made of multiple separate meshes each having a different material applied to it
- you convert that into a single proxy object which results in a single mesh with multiple elements
- this proxy has only one material applied to it (since a single proxy cannot have multiple materials applied to it - like the original objects did)
I am sure that the proxy is created with different material IDs so one solution would be to create a new multi/sub material, apply it to the proxy object, and find out which of the original materials should be plugged into which of the multi/sub slots.
One way to find out would be probably to temporarily convert the proxy into a mesh and check which material IDs are applied to which elements. Alternatively, you could plug some odd-looking material (e.g. pure red) into each slot of the multi/sub material and this way find out which mesh element should be using which material ID.
I am afraid at this point we cannot offer a one-click solution, but we may improve this in the future.