Import google sketchup meshes (.skp) textures to UDK

[Mikalichov]

Hi everyone, so I'm working on a research project that requires me to build a simple 3D environment. My focus is on the actor scripting rather than the actual designing part, so I'm planning on assembling something "quickly" with google sketchup models found on google warehouse.

But. I can manage to import the .skp into UDK, but can't find how to bring the textures with them.

The model I'm mainly working with is this:



I know how to import it in 3DS Max, add collision, and convert it to .ase, no real issue there. I can then import it into UDK, as a mesh:



The problem is that I have no idea how to bring the textures with it.. I can export the textures in 3DS, but they end up all separated:



Since I can't select individual faces on the mesh (probably because of the import, but I might be wrong), I can't apply these textures one by one, and would need a way to get a "texture map" directly from 3DS to UDK, for example as below:



I'm not expecting a full tutorial, but any hint about what direction I should follow (change my importing method? unwrap the textures in 3DS and rewrap in UDK? apply directly in UDK?) would be greatly appreciated. I'm a total beginner at both UDK and 3DS (and 3D "modeling" as a whole), so I'm not familiar with most terms, which limits my google-fu. Sorry for the lengthy and pic-heavy post too, but I prefer to detail my issue clearly

Thanks!

[JessieG]

You need to layout the UVs for those models and apply textures in a format that UDK can actually use (the texture has to be a size that is a power of 2 and a format like Targa that UDK will accept. )

So you need to use photoshop to redo pretty much all of those textures. There's no other way.

[Mikalichov]

Ok, that's a good hint, thanks.

But once I get all these 64x64 or 128x128 textures, how can I apply them? Right now, I can't select individual faces of the mesh, it's considered as having one big face, so if I apply a material, it just covers the whole mesh.

[JessieG]

Well you're not supposed to use different textures for each individual face. You can get away with using more than one for some meshes (pretty sure it's multi-sub materials in Max) but generally you want to combine those separate textures into one texture to use for the entire mesh. You need to learn about UV unwrapping to figure out how this is done.

[joshua.fontany]

You might want to use Max's "Render to Texture" feature to 'collapse' the multiple materials into one texture. I haven't used max for this, but did a similar thing in maya.

Here's a youtube video I found after a quick search (Max's term is "render to texture" but you will also see "bake to texture" alot.. mainly to bake Ambient Occlusion, normals, or lightmaps). Yeah, just previewed this and this seems like what you want. Be aware that he doesn't re-map the "2nd" UVW so there is a lot of wasted space on that map.

http://www.youtube.com/watch?v=-KyKl7_K_tg

[Mikalichov]

Great, that helped a lot! Thanks to that, I managed to finally unwrap the texture map I was looking for:



I'm not sure about what "rewrapping" is so I'll work with it as it is for now, even with the wasted space. So I then imported the .tga obtained through the "render texture" into UDK, as a texture, and created a material out of it (linked the "texture sample" to "diffuse lightning"), which I applied to my mesh. First, the mesh just turned black, but I obtained some "better" results by ticking on the "use precision UV" box (which might be a bad thing to do, don't hesitate to correct me). But still, something isn't right...



Obviously I need to correctly wrap the texture on the mesh, but not sure how that would work. As I see it, it would require the picture to have coordinates regarding what goes where, but that doesn't seem to be the case. Right now, I don't even see how UDK could know how to correctly wrap the thing. I looked up "wrapping textures in UDK", but with no results.

Any hint on where I missed something?

[reinrag]

You need to create UV's on your mesh in your 3d software, then import all those textures into UDK and combine them all into one material, then place that material on your mesh, it's a simple process i'm sure you'll figure it out, if you need more details or a proper explanation, let me know, btw funny signature

[Graylord]

You should also do the texture, AFTER you have done the unwrapping of the model. Trying to make the unwrap fit a ready made texture map is going to be absolute hell.

[Rogdor]

Having tried to fit SketchUp into my UDK workflow for the past year: My honest opinion is it's best for just prototyping something quickly. SketchUp's lack of real UV tools makes your pipeline convoluted, so you'll end up spending so much time trying to fix your UVs: It would be faster / easier / better to recreate the models in other software.

Plus, sooner or later you're going to run into smoothing group issues as well, because SketchUp's smoothing does not match UDK's importing, at all.

I hate to sound like a naysayer, I really do, because I know that using SketchUp is a completely different discipline than other 3D software. It's not bad software, just a poor choice for this purpose.

[Mikalichov]

Having tried to fit SketchUp into my UDK workflow for the past year: My honest opinion is it's best for just prototyping something quickly. SketchUp's lack of real UV tools makes your pipeline convoluted, so you'll end up spending so much time trying to fix your UVs: It would be faster / easier / better to recreate the models in other software.

Plus, sooner or later you're going to run into smoothing group issues as well, because SketchUp's smoothing does not match UDK's importing, at all.

I hate to sound like a naysayer, I really do, because I know that using SketchUp is a completely different discipline than other 3D software. It's not bad software, just a poor choice for this purpose.

Oh, I'm not using sketchup per se actually. I use sketchup models I found online, but work mainly through 3DS MAX.

[Mikalichov]

Ok, so I fixed my problem, thanks for your help guys As it was hinted, what I actually wanted to do (extract the already existing textures as a map) was not feasible unfortunately. I had to make new UVs for the object, render to texture, and then reorganize the different textures on this texture map.

And voilà:


Due to poor UV mapping, the resolution is really bad, but at least I know it's possible. Thanks again!

[JessieG]

I suggest breaking that mesh up into smaller pieces do you can get more resolution to work with for each chunk. Also things like windows and doors should be separate meshes to have even more UV space and the ability to differentiate them from the rest of the mesh (with reflections, transparency, etc) without using one overly complicated material.