The Mysterious Case of the Inverted Iris in Blend Shapes
In the fascinating world of 3D animation, sometimes things don't go as expected. One of the classics is when we apply a blend shape and discover horrified that our character has the iris backwards 😱. As if it had seen a ghost or something worse: a topology error.
"In animation, problems are usually inversely proportional to the time we have to deliver the project"
This phenomenon occurs frequently when working with duplicated geometry to create facial expressions. The software doesn't guess our intentions (yet 🤖) and makes decisions based on the object selection order.
How to Tame a Rebellious Iris in 3 Steps
- Step 1: Delete the problematic blend shape (no fear, they don't bite)
- Step 2: Select the modified object first (target)
- Step 3: Then, holding Shift, select the original (source)
In Maya, the process is: Deform > Blend Shape. In 3ds Max with Morpher, the logic is similar. The trick is to remember that the last selected object is considered the base 🎯.
Precautions to Avoid Scares
Before celebrating that you've solved the problem, verify that:
- Both objects share identical topology
- They are perfectly aligned in space
- There are no pending frozen transformations
If after all that the iris continues behaving like a rebellious teenager, you can always change the color and say it was an intentional artistic effect. After all, in 3D art as in life, sometimes errors are just opportunities in disguise... or so we tell ourselves to not cry 😅.