Question about sculpting modular asset

bwista · Dec 2011

Hi polycount,

I am having a bit of trouble on how to proceed with a modular wall asset I have created. I have created a tileable wall asset in max, and set up a vertex paint material to show, or hide a dirt overlay(yeah i know it looks bad). I wanted to improve upon this idea, by having two versions of the mesh, one which is damaged and one which is intact, and use a vertex paint material to blend between the two. My question here is, how do i approach sculpting this mesh? Mostly I am having trouble with how to make the grout (on the left and right edges) between the tiles tileable after having sculpted on it in z-brush(Wrap mode has not been working). My approach so far has been to import a mesh into zbrush, and seperate each tile, trim and grout into its own subtool. Im starting to think that this is not the right approach. Basically, after watching lots of tutorials on zbrush and how it works, I am not sure what the best workflow is for importing my mesh into zbrush and working on it.
Screens below

tldr; How do i approach sculpting this mesh to make it tileable?

early shot from max showing clean and dirty meshes

wireframe shot with vertex paint

reference image

bgoodsell · Dec 2011

If your going to go the zbrush route, then focus on smaller chunks of the tile. The texture for this is largely repetitive so you should be able to take and sculpt a 2x2 or 3x3 section of tiles to create some breaks or cracks. Smaller areas means more geometry dedicated to those areas. It will also save you a headache from breaking every tile individually.

Your texel density seems a bit off, like your using the entire texture sheet on a 1:1 ratio with your mesh. I recommend looking at JordanW's Bathhouse scene to see how he did tiles (good tiles are a lot about how light reacts to them) and use it as a jumping off point for your own work on this asset.

knak47 · Dec 2011

I would do the grout with a normal map , not sculpt it. Crazy bump will do the trick. Sculpting such a small detail seams like a wast of time.

bwista · Dec 2011

bgoodsell- You are right about the entire texture sheet being a 1:1 ratio for the mesh. It shows my unfamiliarity with UV mapping. I guess I am just having difficulty understanding how I can UV map this one I break it up into several pieces. I created the diffuse, normal, spec using a different reference photo which I cropped and made tileable in PS. Then I used CB to make the other maps. I painted in the texture using these maps, which felt was a hacky way of doing. Looking at JordanW's scene it appears that he uses a 2x2 tile section as a base.

I really want to use zbrush to force myself to learn it. I have lots of reference of the grout, which I could probably use to make a custom alpha. Would the example below be a good way of breaking this modular asset into modular pieces?
Thanks for the help.

bgoodsell · Dec 2011

It depends on what your going to use this in. If your building this into the UDK, you have several shader options you can use to further help you make this asset modular.

I'd keep the block as one big piece. Your going to drive yourself crazy if you make it break into smaller sections like your proposing below. 5 minutes into placing them and you'll be sick of the process.

For the red blocks, i'd use a secondary material on the object if you have it available. (Again, I assume this will be using the UDK) Those center sections can use the exact same tile texture, but i'd stretch the uv's down in the v direction so the grout on the tile lines up.

I applaud your enthusiasm for trying zbrush, as it will definitely help you understand how to work beyond photo texturing. Grout isn't all that difficult, its just a rough surface with a mixed shade of coloring. Since your baking it down to a normal map, you don't have to go super crazy with the detail. You can use a brush or an alpha (i'd use both, the brush for big details and the alpha for the overall texture) but whatever you choose, keep posing stuff.

Gestalt · Dec 2011

Use the 'thirding' mentality. The texture I'd use would be the square starting at the bottom left red tile, going up to just above the middle/thin tile, and going across five tiles. You can add very subtle variation to it, and using your uv's reuse it for the rest of the surface (so for the bottom piece you are using the whole thing, for above that you are excluding the red strip, and for above that you are excluding everything but the top). You won't need to add a lot of verts to get the UV's needed for that breakup and you still have room for some subtle variation without obvious tiling. Vert painting, decals, another UV channel, etc can be used to add variation.

Edit: As far as making the asset itself, all you would need to make is that one square texture. If you are using Zbrush I would use projection master on a high-poly plane just to make that one section. Capture your maps however you like and then make the low-poly from the texture.

bwista · Dec 2011

bgoodsell- Thanks for your help. You are indeed correct, I would like to import this into UDK (Hopefully sooner rather than later!). Now I think I am confused as to:
A) What the actual geometry should be ie. a tessellated plane (ie what I showed before) vs a more complex mesh where each tile being a beveled extruded square (see pic A below.)

How the resulting UV will be laid out as a result. Does UDK deal well with overlapping UV's (overlapping uvs in lightmaps is a no-no right?) I guess I should nail down what the LP will be first.

Gestalt-I have been unsuccessful using projection master to acheive the level of detail I want with such a big mesh (10 tiles long/high). In pic1 below you can see how muddy the textures look up close and how flat the normal map looks. Breaking my texture up in to thirds seems like a good idea, if it works in UDK.

I also want to take into account in the future I would like to use either tessellation/parallax occlusion to pop the silhouette of the asset. My asset will be used in a setting very similar to the one in the reference photo, so the player will be viewing the asset from a sharp angle frequently. I probably shouldn't get to far ahead of myself. But thankfully I should be able to make some progress with a long weekend ahead. Also, thanks for bearing with me and my painfully beginner questions.

Fig 1 (Xoliul 2 viewport screen grab)

Fig 2 (ignore polycount, heh, many objects are hidden)

bgoodsell · Dec 2011

To answer your questions

A) What the actual geometry should be

Rule of thumb is keep the geometry to match the silhouette. Normal maps will do a better job of faking inward depth than outward depth. I like how you've modeled out the tiles over the grout. For the bake and low poly, that can be flat.

How the resulting UV will be laid out as a result. Does UDK deal well with overlapping UV's (overlapping uvs in lightmaps is a no-no right?) I guess I should nail down what the LP will be first.

With a multiple material setup, you can use a multi-sub material type in 3d max and then set the faces or sub objects to have the material id. When this is imported into UDK the object will have two material slots corresponding to the separations defined by the multi-sub material. Because of this, the uv's can be on one sheet and overlap.

When doing this, its a good idea to define a second uv set for unreal's lightmass system. This should be done anytime you have uv's overlapping (which is pretty common on most objects with modular parts)

I recommend checking out 3d motives tutorials (the one I linked to in particular). Its $22 for a single month to basically rent the entire content of the website. I highly recommend it, as it will help answer a whole bunch of questions you'll undoubtedly have as you continue to produce game art.

Question about sculpting modular asset

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