Friday, September 11, 2020

High Resolution Meshes

Many DAZ meshes come in high resolution. Such HD (high definition or high density) meshes can be exported with the Export HD to Blender script, but once in Blender there was not much one could do with them. With the release of Blender 2.90 last week, this has changed. There is a new tool in the Multiresolution modifier that takes a HD mesh and rebuilds the lower subdivisions levels. Following a suggestion by J Cade, the DAZ importer now uses this feature to build multires meshes from HD meshes.

Here is our HD character in DAZ Studio

Export the subdivided mesh using the Export HD To Blender script.

In Blender, two versions of the character are imported, the HD version and the ordinary version at base resolution. They are assigned to two different collections so either of them can be easily excluded from the scene. Both meshes use the same armature, which belongs to both collections.

The HD mesh has a multires modifier.

If we decrease the number of multires levels the high-frequency details are smoothed out.

The really great thing is that the HD mesh has the same topology and vertex order as the mesh at base resolution, just with a multires modifier added. This means that we can delete the base resolution meshes and proceed as usual with loading morphs and JCMs etc. The simplest way to delete all base resolution meshes is to delete the corresponding hierarchy in the outliner.

The Export HD To Blender script exports the cached geometry that DAZ Studio uses to display the scene. This means that you can control the amount of detail that is exported with the SubDivision Level slider. If you change that slider, the cached geometry changes because DAZ Studio needs to display the geometry at another level, and hence the geometry at that level is exported to Blender.

Be aware that meshes at high subdivision levels contain much data, which means that the export time and file size increase dramatically. Here is a comparison:


Time (seconds)File size (kB)
Export w/o HD        
0.706436
HD Subd 05.4393635
HD Subd 112.7088544
HD Subd 242.51628086
HD Subd 3161.046104954

In upcoming posts we will discuss how to deal with geografts (genitals), and how to bake normal maps from the multires modifier.