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Basic 3D game model workflow?

Hiya,

I am somewhat confused when it comes to the process of modelling assets for games. I know that some people model things in Zbrush (or similar programmes) and then bake that on to a low poly version of the model, but the thing that I am not sure of is in which order everything is supposed to go?

Is the model made first in Zbrush, then UV mapped, then a low poly copy is made by stripping down the high poly version, or is a new model entirely, and then that UV mapped to match the high poly version?

And then after that, there are all sorts of other maps that can be used too (specular, diffuse, normals etc). How/ when in the process are these generated?

I've found various mentions about this sort of stuff, but no clear cut tutorials/instructions and I am unsure about the best way to approach these techniques.

Any help would be awesome thanks!

Replies

  • Zezeri
    Usually you model a Highpoly first in Zbrush/Max/maya/modo/blender and then create a lowpoly and UV it.

    How you make the lowpoly is not important, just make sure that it matches the HP as closely as possible while retaining a sane polygon budget (or more accurate, vertices budget).

    You don't need to UV your Highpoly, unless you want to paint/texture the highpoly itself. Consecutively, the HP & LP UV don't need to match up.

    After you have a UVd Lowpoly matching your Highpoly, you start baking maps.
    Some of these are:

    Tangent Space Normal Map (Details from the Highpoly are "projected" onto the Lowpoly and saved in this Bitmap in tangent-space)

    Ambient Occlusion Map (Areas that are more occluded are darkened. This is useful as a mask for textures to simulate i.e. dirt accumulating in more occluded areas, such as holes or intendations in the Model. You can also bake an additional AO map by baking from LP to LP and then combine this map with the traditional HP=>LP baked map. Earthquake has described this method in the wiki iirc)

    Color/Material-ID Map (Basically you assign simple color materials to your HP, where each color represents one distinct material, i.e. red = iron, green = wood etc. Useful for texturing)

    Curvature Map (This map contains both a Cavity and a Convexity map. So it marks areas that are concave, like small cavities and intendations. And it marks Convex areas, like edges on your Model. Useful for masking, such as Edge wear, or again, dirt accumulation in cavities.)

    As I've already mentioned, most baked out maps are very useful as masks during the texturing process. So now that you've baked everything out (There are more maps than I've listed, I just picked a few), the actual texturing process begins.

    For most PBR engines, you'll need 4 textures, also depending on whether you use the metallic (UE4) or the specular workflow (CRYENGINE).
    Albedo, Specular, Normal & Glossiness are what you would need for CRYENGINE generally.
    For UE4 you'd need Base color, metalness, normal and roughness (inverse of glossiness).

    You can either do this in Photoshop manually by using layers and groups, looking up physical values and using reference, logic & observation.
    Or you can use tools such as dDo, Substance Designer/Painter or Mari.

    If you've already UV'd and textured your HP, you can of course just bake down these textures to your lowpoly and are finished :)
  • Eric Chadwick
  • Eliket
    Wow! Thanks so much for your answers guys. This gives me a much, much better idea of how it all fits together! :)

    I'll get started reading through all those wiki's too - starting to get excited about making my own models and such using these techniques!
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