UV Mapping - How to use multiples materials and images for one object

[micheus]

Wings3D force us to use only one material for an object when we UVmap it, even it having many materials assigned before unwrapping.

So, let say you have assigned many materials to your object/model; then you unwrap e create the UVmapped material - there will have only one for the entire object. But, what you wanted were to preserve each material assigned previously to its mesh area. That's what I intend to show in this "tutorial".

As a workaround I use this workflow to get that "fixed":
What I show in the video people can say it's not a real word case, but the process is the same. You just need to add a step I jumped by using pre-build images - after you used the Create Texture button, go to the Outline window, make a copy of the <obj_name>_auv using Duplicate in the context menu and rename it. After that you can assign this image to the initial material (as show in the video).
Everything else stays the same: you make the image external, paint it and refresh inside Wings3D.

Just a tip, in case some one still don't know about:

It's a good idea to unwrap the model only after you finished it completely.

After UVMapped, if you continue refining your model you will need to unwrap it again. That is not really a problem - it's boring. Just use the UV Editor for that - in Body selection mode - to fix any mapping distortion and rearrange the mesh position over the image.
Sometimes Remap UV->Stretch Optimization works better and give us less work.

Important: when finish fixing the map do not use Create Texture option - you already have one - just close the UV Editor window

[Nova]

Looks like you're basically just reassigning the materials, which is cool, but for a more complex shape, the re-selecting process can be a hassle. A trick there, is to convert all your materials into selection groups before you UV, and then reapply the old materials using your selection groups.

Also, a step that could save you a lot of time in that video is to use the Rotate>Chart to X/Y in edge selection, it'll rotate the entire selected island. Saves you from having to figure out the angles to rotate by.

[micheus]

but for a more complex shape, the re-selecting process can be a hassle. A trick there, is to convert all your materials into selection groups before you UV, and then reapply the old materials using your selection groups

I did't get your point here. Once you have the uvma material in the Outline window you just use the select option for the material. Why would we have to add a second way to select the same thing?

[Nova]

Lets say you have a model with 2 materials, metal and wood. You go through the AutoUV tool and it creates a new material that everything gets assigned to, you no longer have metal and wood. But if you have gone Material>Select and made a new selection group for each material, then after the creation of the new material you select one selection group and re-apply it's old material, then do the same for the other.

If this was a complicated model, and you hadn't saved selection groups, you would have to reselect the faces you wanted to be metal and wood respectively once more. Saving the selection groups skips that step.

[ggaliens]

Was thinking about an easy way to say "back up" materials into stored selections (named) ... but I think maybe the material definition itself can't fit into a stored selection.

Might be better for someone to enhance AutoUV so it could reset materials when it is done ... but that too might be a tall order. That material AUV may be needed to make the image "stick" ?

[micheus]

Lets say you have a model with 2 materials, metal and wood. You go through the AutoUV tool and it creates a new material that everything gets assigned to, you no longer have metal and wood.

If I understood right, start with two different materials and then create an uvmapped material that include the entire area used by both was not the scope of this thread. I'm going to update the first post to mention this. Thanks to explain and let me know if that post is still not clear enough.

But, in this case, what I use to do is make the selection area, paint each area (using the palette) and creating a selection group (as you do) - just this. If everything will be put in the trash after apply the UVmap, there is no reason to create materials and the selection groups is enough.
Also, you still have the possibility to used the vertex colours to tint each face when creating the texture.

[ggaliens]

Since AutoUV messes with materials assignment ... why don't I go ahead with a BACK-Up materials to the selection groups ... and people could use i before AutoUV if they wanted. And of course there would be a corresponding selection groups to materials.

Is this a waste of time for me to do ?

[micheus]

Everyone will find his own way to workaround some situations like that. There is no wrong way, maybe a faster way.
I just made a video sharing my workflow for those which didn't think about before and they think there was no way to do that.

Fell free to make a video for that approach. The more choices people have, the more knowledge they acquire and the community will thanks.

and just taking a ride on this subject, there is a thread to talk about possible improvements to AutoUV: Some AutoUV ideas

[ggaliens]

Something I tossed together quick. I'll try to escalate it to core Wings ...

https://www.youtube.com/watch?v=9ovj3gNGF2g

[Nova]

A nice little addition imho. Hope it gets into core