WEEK 4 - Re-topology and Research

Combining the mesh and Re-topo-

Firstly I have combined the separate pieces of the wolf into one group in Z brush. Which can be seen below:

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Next by using the re-mesh tool then modifying the geometry with z re-mesher I got these results.

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This is going to be the first pass of my high poly model, the mesh is completely combined so that there are no hidden surfaces which could cause issues later down the line.

Unfortunately, when comparing the original blockout to the high poly model I feel that a lot of the shape in the fur has been lost instead of complimented. I feel that this detail is lost during the re-meshing stage. The problem arises when, in order to keep the detail of the blockout, a high poly count is needed which I find hard to control when dealing with primary forms.

To help with this I am going to retopologize my low poly model, something that will need to be done anyway to get the proper topology I need for animation, giving me a better base mesh that I can subdivide and control easier during sculpting.

Maya retopo:

There are alot of different programmes that allow you to retopologize a model in slightly different ways, the main principles of topology suitable for animation always remain the same however. My main source of reference here is the book Stop Staring which has a large section dedicated to understanding the best topology when creating models. Although a human head is used in the example, the basic points can definitely still be utilised. Edge flow needs to work with the direction the character's skin will move, focusing on facial landmarks (such as the brows or crease of the mouth when smiling) that line up to the topology. The best way of doing this is by using circles that can readily facilitate deformation in the mesh.

At first I attempted using the Zbrush topology tool after following a quick tutorial for body retopology on youtube by ‘Danny Mac 3D’ found here: https://www.youtube.com/watch?v=ns5iRWRii5c&feature=youtu.be

For a body retopo I feel like this method works really well, for what I want to do however, less so. I was encountering multiple problems when creating edge loops that needed to be symmetrical, and found that the tool itself was hard to use around the mouth and ears.

Therefore I decided to stick to the method that I am already familiar with, which is that of the quad draw tool in Maya.

Firstly I imported the base mesh as an obj at its lowest subdivision level but felt that it didn't contain enough detail so instead imported the same mesh at a higher subdivision level.

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The meshes in maya and lining everything up:

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I also imported the teeth and eyes, however I won't be retopologizing them as I made sure they had a good base mesh as I was creating them. It’s always best to do this when working with smaller detailing and cuts out a lot of hassle later on in the pipeline.

The uncombined block meshes initial topology can be seen here:

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Due to the way I have blocked out the primary forms I can easily see how the topology of my model will need to be broken up.

Here I have set myself a quick guide to follow for the basic shapes, as I move down into the mane, the topology will become more uniform as there will be little movement here:📷

To begin I make my wolf head surface active (To make a surface active it has to be one mesh which is why I exported from zbrush as an fbx rather than OBJ). Once active, I activate world symmetry and then go into the Modelling toolkit and select Quad Draw.📷

I started by putting some basic loops around the areas I needed to and built up the forms quickly resulting in the mesh seen bellow:

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This first attempt is not quite correct as can be seen around the mouth. The topology is not dense enough and although it would do the job, I am not satisfied there is enough detail in the cheeks and jaw.

Attempt 2:

This attempt has gone much better and I’m happy with the resulting mesh. Next I will take this into Zbrush to attempt my high poly sculpt again as well as begin to test some rigging and blend shapes.

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On trying to re-import this mesh back into Zbrush, Ngons and tri’s are present, which Zbrush doesn't work well with. Therefore I’m going to use the mesh → cleanup tool to try and remove them.

Using this tool I have been able to find some accidental bad topology… Hopefully my next import should work.

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It worked!

In the future I should use this tool after I’ve finished sculpting in maya to save time when checking topology.

The mesh (I shall work on the extra bits of the model next, like teeth, eyes and tongue) is now in Zbrush, ready for UV’s, high frequency detailing and blend shapes.

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Teeth: sculpting for good topology In Z brush

UVs:

Next I’m going to UV my low poly model, although Zbrush does have a UV unwrapping tool, I am already familiar with Maya’s so can cut a lot of time trying to learn a new pipeline. If I have time later I may go back and look at the Zbrush method, I already have a few youtube tutorials I found on it.

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The predetermined UVs are unusable (as to be expected) so I’m going to delete them and start from scratch.

To begin with I use the cylindrical tool to create a good base to use. For the UVs I’m using

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There's still quite a lot of stretching in the UV but I’m going to try this one as a first attempt.

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Meanwhile in Zbrush….

I have completed the first High poly mesh, by using the blackout as the base,

In retrospect this was unnecessary as it means there isn't an even topology around the whole mesh, but for a test it should do for now. I’ll likely work back into this later after re-meshing it.

High Poly Mesh:

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Next I’m bringing the high poly into maya after decimating it ready to export both meshes into XNormals, which is a free tool I can use at home to bake normal maps and other textures.

In Xnormal I need to remember to use the Ray distance calculator when creating normal maps.

The final map is as follows:

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Using Arnold Renderer, I have then placed this bump map onto my low poly mesh the results aren't great.

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The bump map works, and when higher divisions in the mesh (and smoothing groups) are introduced it looks much better.

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Polygons are however showing up so I’m going to re-bake the normal map on the smoothed low poly mesh to see what kind of a difference this makes.

New map:

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Same issue is still occurring in the Arnold rendered.

Will come back to this at later date Time permitting.