best way to have multiple materials on an object?

Okey depending on what modelling software you are using you can apply multi-subobject materials in your 3d editor.

Im using max, im assuming you just apply material to each polygon you want in maya and then export it.

For max just apply a multisub object material to the whole mesh and set the material id to whatever polygon you want each material to be on.

Im sorry if thats a pretty bad explanation. But its really simple in practice. Just setup the material as you want it in Max or Maya and then export it like that and you will have several material slots inside UE4 aswell.

UDK Combining Multiple Materials - YouTube < this explains how to add multiple textures onto one mesh.
You can have multiple UV chanels, but each channel will up the drawcalls, and the less drawcalls the better :slight_smile:

With the approach in this video, you will be using only one UV map :slight_smile:

I have a veichle model ready. It needs rubber, painted metal, shiny metal etc materials.
I saw in the tutorials that either I need to asign different material slots or have a color map and material funtions to define materials separately.
Question: for optimization point of view which is better?

Also:my current model has been mapped to the same UV map. Is that ok for both approach?

Extra question: is it possible to combine diffuse color map with color mask somehow? (to elaborate: I would paint some parts of the model to their final color and I would paint some other parts to let’s say pink. Then i’d keep the normal colors on the model except the pink parts which would be replaced by an other material.-hope this question makes sense :slight_smile: )

For my model I plan to uv map: one for textures and one for lightmaps (the model is mirrored so in the first uv map my goal is to save texture space by overlapping polys).
My main question is though: which method is the better, assigning material slots in 3d app or paint a color map/mask and use material functions to define different materials for a single slot.

he actually doesnt want to use multisub.

If you mirror the model, then your normals will be messed up, unless you mirror the texture (in clamping options) in ue4 and made sure the mirrored parts are propperly set up in our 3d program of choice.
you can have overlapping textures for the diffuse, but not for the lightmap!

Either way is fine, if you render to texture you can apply as many textures you want and render out 1 texture.
the latter works just as fine. it depends on what you prefer and what increases your workflow speed.

Starting with 4.2 mirrored usb with normals will be supported when UE4 starts using FBX2014. This was listed on the 4.2 preview page.

But for now not available, i for one welcome the addition though :slight_smile:

Hmm. i use blender and at least in unity i had no problem with mirrored mesh/uvs. I’m gona try with a simple model to see how it works. But good to know even if it won’t work it might in the future.

In the event someone wants to see a quick workflow on how to export to and add sub-materials in blender, here is a tutorial on how to perform this;