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Game Editing => Video Channel => Topic started by: kat on March 06, 2014, 10:25:57 PM

Title: Make a mesh from a texture (using Transparency)
Post by: kat on March 06, 2014, 10:25:57 PM

Using a 'window' images from the 'village' assets of Return to Castle Wolfenstein, the video above shows how textures can be used as a guide during the creation of more detailed or shaped meshes that can augment an already existing normal-mapped texture set (diffuse+normal+specular etc.)

Scenario
In certain situations there might be a need for in-game structures to be modelled to contain more detail than can otherwise be had using normal-mapped texture sets assigned to flat plains. If textures already exist it might be possible to use them as a template or guide around which a model can be made in Blender (or other application with the following support).

Problem
In wanting to use pre-existing textures as a basis from which game models are to be made (and mapped using said-same images employed to make the mesh), editing can be tricky because UVW mapping tends not to be held in place during the generally 'destructive' modelling process - adding and moving edge-loops might shift or distort any UVW maps previously assigned for example. Whilst Blender has a number of properties available that might otherwise ease the UVW map distortion issue in a general sense, they do not always have a practical application. Ideally, rather than trying to prevent the problem the artist might find it better to 'ignore' it whilst being able to 'see' the texture at all time.

Solution
A 'see-through' mesh can be facilitated by making a duplication of an original Object (always work on a copy) and making any assigned assigned Material/s 'unique' (Single User data-blocks). Once done activate material "Transparency" and reduce the value of the property so the mesh becomes see-through thus allowing the mesh to be editable in Edit mode; the mesh can be shaped whilst the original textured version is visible as a guide.
Title: Re: Make a mesh from a texture (using Transparency)
Post by: ratty redemption on March 08, 2014, 01:20:38 AM
interesting and very nice textures you have there.

i was recently thinking of testing uv project modifiers to project a flat non deformed reference image onto the mesh being worked on. if i remember correctly they also work in edit mode.

edit: just did a quick test and yes, uv project does work very well for this task, from what i can see. both in low poly sculpt grab mode, and edit mode.
Title: Re: Make a mesh from a texture (using Transparency)
Post by: kat on March 08, 2014, 01:36:11 AM
Aww nuts! I forgot to mention the texture is from RtCW again. It's one of the windows from 'village'. I'll amend the text info above.

Yes, so long as you're able to see the target (what you *should* be doing) whilst working other techniques might work just as well. As with the coloured wireframe rendering (http://www.katsbits.com/smforum/index.php?topic=583.0) video, the approach above is pretty straightforward to set up and quite handy if a number of mesh assets are needed.
Title: Re: Make a mesh from a texture (using Transparency)
Post by: ratty redemption on March 08, 2014, 01:45:14 AM
he he, well your textures are as good as the original rtcw ones.

and agreed, there are probably several different methods we could use to model quite quickly while not having to constantly be unwrapping or fixing the distorted uv's.

project modifiers can use 2d plains to project the images, but they took me a while to get my head around them. your method here is quicker to set up i think, and i might use both these methods with the modeling i'm soon going to be working on.