Background

WANNA rendering engine is capable of showing beautiful gems like diamonds or sapphires. Some of this beauty is proprietary and requires special model preparation; this article describes how to achieve the desired effect.

Preparation

1. Set up Substance Painter.
2. Set up Gestaltor.
3. Download archive with various gemstone cuts.

Suggested workflow

The best way to model items with repetitive gems is to use instances. Unfortunately not all modeling tools support them, so we suggest the following workflow to work around it.

1. Create base model geometry in any tool of your choice. You don't need to add any gems at this point, they will be added later.
2. Texture 3D model using Substance Painter or any other software.
   • If you intend to have gems under transparent glass, for example on the watch dial, that glass should be made transparent using Transmission in Gestaltor - see #8 in this list.
3. Export textured model to gltf and import into Blender.
4. Add gemstones to the model using samples from the archive and Reset their transformations (this is temporary solution to a problem we uncovered). All gemstones of the same cut should be instances of the same mesh.
   1. Do not bake AO under gems, otherwise black spots will be visible through the gem.
   2. Leave a bit of space between gems and materials that hold them to avoid coplanar meshes.
   3. All gems should be subnodes of the top level main node to correspond with General model requirements for 3D Viewer 
5. Name materials used for gems in a special way:
   • Any diamond-like material with visible dispersion (diamond, cubic zirconia, etc.) should be called wanna_diamond_XXX, where XXX can be replaced with anything. For example, wanna_diamond_1, wanna_diamond_2, etc. Materials for the gems in the archive are pre-set to diamonds.
   • Any other gem material (sapphire, emerald, ruby, etc.) should be called wanna_colored_gem_XXX, where XXX can be replaced with anything.
6. Set base materials parameters to the following for all gems. If you are using cuts from our archive, they are already preset there.

7. Export model to gltf with deactivated Vertex Colors checkbox. Open it in Gestaltor, as the rest of the settings will be set there.

8. If your model has a glass that should be transparent, select its material in Resources and set Extensions → Transmission → Transmission Factor to 1. 

9. Adjust Extensions → Volume → Thickness Factor, Attenuation Distance and Attenuation Color to match the reference.
   1.  Attenuation color should match base color and gem color on reference
   2. Thickness factor should be roughly the same as gem bounding box dimensions (0.001~0.004 on this example)
      
   3. Attenuation distance should be roughly the same as thickness, but you can adjust it to get desired color (lower values result in darker color and higher values - in brighter)
      

      If color not matches in studio and Gestaltor or other viewers check if Scale is 1

       

10. Export result to gltf and upload to Wanna Studio.