Creating transparency maps for cloth?

[Anhslaught]

Hi,
So I did the tutorial on ripped cloth modeling here and to do that, I had to work on a high resolution mesh. To delete some of the parts for the ripped appearance, I had to hide and delete some parts. This technique required that I deleted the lower division. So now I’m stuck with only a level 7 division ripped cloth. I can’t reconstruct this now also.

Is there a way I can still use this and create a transparency map, so that I can bring into Maya? Or is it a useless piece of cloth now?

[MagmaPixel]

This is an almost impossible question to answer. Anything I say could destroy your work even more, because we have no idea what you built, or how you built it. Punching holes can cause problems if it’s not handled right.

Shooting from the hip:

You probably need a retoplogy. There are many ways to do this, and zbrush has topology tools built in.

You’ll be creating a 2nd low poly model to subdivide a few times, and then you’ll project all your old details onto it. That’s the only way to rebuild clean, level 1 geometry. (There are some quick and dirty methods too, though.)

I suspect you might have been better off not cutting a hole in the mesh. Since you’re going to make a transparency map for the hole (I assume), you could just leave the mesh solid, and draw black areas anywhere holes would exist. Export that black and white texture, then plug it into the transparency on your shader. Instant hole.

I’m doing a lot of guessing here. If you want to add some screenshots and more details, I (or others) can give better advice.

[Anhslaught]

Thanks for the response! here’s a screen cap of what I got. Everything in this picture has subdivisions except for my cloth.

Does this mean I would have to redo the cape’s alpha in photoshop? Isn’t there a way to project this high resolution out as a transparency map?In Mudbox, I saw this video where it has a feature to paint transparencies, I was wondering if we could do this on zbrush one way or another?

Attachments

[MagmaPixel]

Ah, ok. I think I know what you’re wanting.

Mudbox lets you paint transparencies, specular highlights, and just about everything else you can imagine, because it uses actual Maya style shaders. You’re painting separate maps that are automatically plugged right in to the live shader effects themselves. Very cool stuff. Doubly cool because you see transparencies on the model while you paint, instead of grayscale maps.

Does that sound like what you saw??

Zbrush can do some of that, but not all, and not in the same way. We’re not there yet. Unless I’m forgetting something, Zbrush can display one texture map, one normal map, and one displacement map at the same time, per object. You can easily create a specular map, for instance, but you can’t have a specular map and a diffuse (color) map showing on the model at the same time. (Though you can sort of cheat by using multiple shaders to simulate layered maps. This only works well in zbrush though. There are no maps to export.)

Following this info, if you want to create a transparency map for another 3D app, you’ll need to create a texture map in zbrush, using polypainting and convert that to a texture for export. This polypainting/texture would need to be a grayscale image. So as I said in an earlier post. Your cloth would be stark white (solid), and your holes would be black (empty) spots. The cloth would be 100% solid geometry. No real physical holes.

You could also adjust the cape’s alpha in photoshop as well. You have options.

This is just the bare bones. You can create maps in somany ways. You just can’t always see them live in zbrush.

The difficulty we have is that those are actual holes in your geometry. I think no matter what you do, the cloth will have to be retopologized in one way or another. You could leave the holes, or fill them in, and create a transparency map for them, but either way, you need new geometry. If you allow the holes to stay, you can probably transfer any details to a new lower poly mesh, as long as that mesh lines up with the original, including the holes.

Is this helpful? Did I misunderstand what you need? If so, what exactly is the transparency supposed to be used for? (I assumed it was for the holes.)

[Anhslaught]

Ah, ok. I think I know what you’re wanting.

Mudbox lets you paint transparencies, specular highlights, and just about everything else you can imagine, because it uses actual Maya style shaders. You’re painting separate maps that are automatically plugged right in to the live shader effects themselves. Very cool stuff. Doubly cool because you see transparencies on the model while you paint, instead of grayscale maps.

Does that sound like what you saw??

Zbrush can do some of that, but not all, and not in the same way. We’re not there yet. Unless I’m forgetting something, Zbrush can display one texture map, one normal map, and one displacement map at the same time, per object. You can easily create a specular map, for instance, but you can’t have a specular map and a diffuse (color) map showing on the model at the same time. (Though you can sort of cheat by using multiple shaders to simulate layered maps. This only works well in zbrush though. There are no maps to export.)

Following this info, if you want to create a transparency map for another 3D app, you’ll need to create a texture map in zbrush, using polypainting and convert that to a texture for export. This polypainting/texture would need to be a grayscale image. So as I said in an earlier post. Your cloth would be stark white (solid), and your holes would be black (empty) spots. The cloth would be 100% solid geometry. No real physical holes.

You could also adjust the cape’s alpha in photoshop as well. You have options.

This is just the bare bones. You can create maps in somany ways. You just can’t always see them live in zbrush.

The difficulty we have is that those are actual holes in your geometry. I think no matter what you do, the cloth will have to be retopologized in one way or another. You could leave the holes, or fill them in, and create a transparency map for them, but either way, you need new geometry. If you allow the holes to stay, you can probably transfer any details to a new lower poly mesh, as long as that mesh lines up with the original, including the holes.

Is this helpful? Did I misunderstand what you need? If so, what exactly is the transparency supposed to be used for? (I assumed it was for the holes.)

Yeah it’s exactly what I’m trying to do. I’d like to animate the cloth, but having millions of polygon isnt practical so I need a normal map and a transparency map to get that effect. I can try the retopo and then project details on it, but I’m still unsure how to get the exact details since there are holes in my thing. I reall don’t know how the process goes. It’s confusing. I think I could use a video or some type of tutorial to get me started. :-p

[MagmaPixel]

You have options. I’m going to speak broadly, without a ton of detail.

Option #1: (Maybe no transparency map needed.)

-Retopo to create less geometry, but do it in a way that there are still holes in the mesh.
***a) You will lose details around the tears unless you retopo a lot of geometry in those areas.
***b) Alternatively, you could leave the hole edges with a very low poly count and paint a transparency map later to make the edges look torn and roughed up. This is probably best for this method.
-Subdivide a few times
-Project details

Option #2: (Required transparency map.)

-Tools > Geometry > Close Holes
-Sculpt to clean up the area if needed. Clay works well. Minor touch ups only.
-Retopo
-Subdivide a few times
-Project details.

(Your original sculpt will be totally ruined at this point, but that’s ok, because you’ll have a brand new one.)

Notes:
These two methods are based on the assumption that your cloth is one polygon thick. If you cloth is an actual shell (hollow inside) there may be more adjustments to make.

I’ll try to guide you in the general direction if you need help with anything.

Zbrush retopology tools are well suited to these parts of your model, as far as I can see.

Good luck.

[Anhslaught]

Hi, I tried doing this without having to ask too many questions before I tried it out first. I’ve been failing a lot, its not looking the way I want it to. I retop’ed using NEX in Maya, then I brought it in to project all. I thought about doing a displacement map export, but found out…it didn’t work too well. Any other ideas? Something clear and understandable?