K-Mart | Trucker Cap

K-Mart Trucker cap | breakdown

The challenge on this object was the fabric net. I had a 3D scan as a base for modeling and reference, but the scan was not usable for some parts, especially the net. My solution for this was to rebuild the net from scratch, using Nanomesh in Zbrush.

First thing I did before I even started with anything else, was to test out nanomesh on a dummy. I’ve never worked with it before, and I had to check if it was the right choice. I was impressed on how easy and straight forward it is to work with and decided to walk this path.

workflow summary

  • pose, scale, transform the model so it fits in real world proportions
  • clean up the scandata
  • Nanomesh creation
    • create the knitting pattern
    • create the target meshes for the pattern
    • tweak the pattern so it matches realistic proportions and scale
    • apply the dynamic subdivision
    • decimate the mesh to reduce polycount
  • retopologize the rest of the model and make UV’s
  • divide the lowpoly and project the scan detail onto the new clean meshes where possible
  • bake the color information from the scan data onto a new texture
  • create the rope with a custom Zbrush brush

scans

Nanomesh workflow

knitting pattern

Nanomesh is a tool in Zbrush that lets you duplicate a mesh as a pattern over a surface, in my case a knitting pattern.

So, the first thing I had to figure out, is how does this specific knitting pattern look like. For that I did some research, looking for similar caps on google. In the end I used a cap that I had at home for reference.

On the right you see the pattern I modeled in Modo.

ZBrush contributes the pattern over the mesh using polygons, so it is very important that the pattern fits perfectly into a 1×1 space and all the border points fit exactly on the edge.

knitting_pattern

target mesh

In order to get a clean result, the target mesh, on which the pattern is applied, has to be carefully tweaked.

  • The mesh flow will dictate the direction of the fabric pattern. 
  • The resolution of the final pattern, will be dependant on the polygon sizes. 
  • The polygons all need to be the same size, otherwise the pattern will look distorted and uneven.

Below you see how the knitting pattern fits onto the mesh. 

Nanomeshes applied

Nanomesh works with dynamic subdivision, so before it is applied, it’s not real geometry. 

After applying all the Nanomeshes, the hole model had over 30 million points. After optimization with decimation master I ended up with 2.9 million points.

lowpoly and UV's

After all the Nanomeshes were done and applied, I retopologized the rest of the model and created the UV’s for it where it was necessary. Not all the parts needed UV’s since the knitting pattern was only rendered with a material and without any textures.

 

Highpoly and texture projection

Now, I projected the scandetails from the scan onto the newly created, clean mesh.

Luckily on this model there was usable color information, so I could project i onto a new texture with proper UV’s.

As a final step, I added the rope on the front with a custom Zbrush brush. 

This is how I passed the model onto the client for rendering.

It was a really fun challenge and I’m glad I learned so many things with this object.

 

Thanks for reading!