type error getclassinstances requires maxclass got undefined

[vinidelimaa]

I got this error "type error getclassinstances requires maxclass got undefined" always when I try converting an object inside Corona Converter.
It also occurs when I open some objetc or assets inside 3DS MAX 2021.

I just saw the Autodesk helper forum, but there they recommend to install the Vray, also if I'm using Corona Renderer.

Anyone knows the solution of this problem??

Thank you!

[maru]

That is correct - you need to install V-Ray to be able to convert V-Ray materials to Corona. Otherwise Corona doesn't know what to convert from.
If you are converting from some other renderer, you need to have that renderer installed.
It does not have to be activated though. Just the installation is enough.
See: https://coronarenderer.freshdesk.com/support/solutions/articles/5000549705

[vinidelimaa]

Thank you for the answer!

And sorry for the amateurism, but if the objetc is in "3D OBJETC" (OBJ), I have to convert anyway?

[maru]

If you have an object in .obj format, you can just import it in 3ds Max.
If this object has V-Ray material applied to it, you will be able to convert this material to a Corona Material using the converter script.
Please check this guide and the video in it: https://coronarenderer.freshdesk.com/support/solutions/articles/5000549705