ZRemesher and Hard Surfaces
ZRemesher is optimized to work on all kinds of model structures and shapes but will by default produce better results with organic shapes. However, with some extra effort on your part retopology of hard surfaces and mechanical models can be greatly improved.
Unlike organic shapes, hard surface models generally have drastic changes in direction along their surfaces and multiple topology variations in small areas. All these topology changes put a lot of stress on the algorithms. With this in mind, requesting a low value for the target polygon count can decrease the quality of the results.
To help ZRemesher, the first step to do is to avoid using a low polygon count and allow a higher value. This gives ZRemesher the necessary freedom to manage these topological changes.
Work with PolyGroups
ZRemesher has two different options dedicated to PolyGroups. One of them strictly keeps the PolyGroup borders (using them as edge loops) while the other uses them as references during the retopology. If your hard surface model is defined by PolyGroups, turning these options on will improve the results. Depending on the model, it is advised to test both options.
If your model doesn’t have PolyGroups, it is benifical to create them to assist ZRemesher. When working with hard surface objects, Tool >> PolyGroups >> Group By Normal will quickly produce PolyGroups based on angles between edges.
At a value of 100, the Curve Strength setting forces ZRemesher to put partial or complete edge loops at the curve positions. Making extensive use of this for hard surface models can therefore increase the quality of edge surface topology. Unfortunately, it can be difficult to accurately place a curve exactly along an edge.
There is, however, an easy way to produce an accurate set of curves based on the angles and edges of your surface:
- First create PolyGroups based on the model’s normals by using Tool >> PolyGroups >> Group By Normal and adjusting its Max Angle Tolerance slider as needed.
- Use those PolyGroup borders to create curves via the Stoke >> Curve Functions >> Frame Mesh feature. Don’t overlook the usefulness of the Border and Creased edges modes.
- Set Tool >> Geometry >> ZRemesher >> Curve Strength to 100, along with any other ZRemesher options that you need. (Like the Keep Groups option.)
- Run ZRemesher.