Becoming a Butterfly
One of the challenges with NatureSims projects is that when you are working at the scale of a butterfly, it is harder to find good third party assets to use. There are hundreds of options out there for plants and other miscellaneous objects online, in the Unity Asset Store or elsewhere. But a virtual flower that looks nice when you’re the size of an average human generally looks pretty terrible when you shrink down to the size of a butterfly. What might have started as a “AAA” asset ends up looking more like a pixelated model from the 1990’s.
The same is often true for the materials and textures you can find. They just don’t look right because we’re working at a substantially different scale. So, before jumping into Substance Painter to paint my models, we took a quick detour to Substance Alchemist to generate some of my own materials.
For this project, players can’t actually see too much of the monarch’s body, since it’s more or less directly behind the player camera. But the player does get a great view of the monarch’s wings so the wing material is particularly important.
Monarch wings, like those of other butterflies, are covered in tiny scales. While these scales aren’t discernible to the naked eye, you can see them clearly under magnification.
This is important because, if you imagine a butterfly scaled up to the size of a person as in the mock-ups above, the wing scales would be clearly visible. In images we’ve found they look almost like a soft fabric, as in the image below.
Alchemist has a pretty amazing feature that lets you generate a material based on a single image. It also has tools to make that material tile well, or repeat in the x and y axes to form a continuous whole. So to create my “wing scale” materials, we used an image of a magnified monarch wing, and made a few fixes to make it tile well. Then we just had to modify the base color to generate wing scale materials in a few different colors, to match the colors on a real monarch wing.
Here’s a screenshot of one of my dark brown wing scale materials, shown in Alchemist.
Once we had those materials ready, we brought them along with my Blender model into Substance Painter. Painter allows you to take a wide variety of individual materials, like the brown wing scales shown above, and paint them directly onto a 3D model. You can then export the combined material for the entire model (in the form of a texture atlas) that you can use in Unity or even bring back into Blender.
For the monarch avatar, we used my wing scale materials for my butterfly wings and a few other materials we found online for the butterfly’s hairy body and dark, chitinous lower legs. We spent the most time on the wings, since they’re the most important, and painted the antennae and proboscis separately. You can see a close-up of one of the wings below along with a top view of the entire body. This won’t be the final version, but works well enough for this prototype.