The Mystery of Non-Selectable Vertices
When working with Unwrap UVW in modern versions of 3ds Max and you find that certain vertices stubbornly refuse to be selected, you're experiencing one of those frustrating bugs that can halt a project completely. The problem you describe is particularly baffling because it occurs on a simple object like a trash can, where the geometry should be fully accessible. The fact that you can only select the vertices on the front and interior while the side remains inaccessible - shown in blue in your image - suggests a specific selection issue related to how the planar mapping is interpreting the face normals or how the selection information is being transferred between different sub-object modes.
Diagnosing the Selection Problem
This anomalous behavior in Unwrap UVW generally indicates specific issues with selection transfer from the editable poly sub-object level to the UV editor. Even if you've verified that the selection is not locked and everything is on the same material ID, there are other factors that can cause this issue.
- Normal problems on the side faces
- Conflict between different modifiers in the stack
- Planarity-based selection that excludes certain faces
- Temporary corruption of the file or Max session
Practical Step-by-Step Solutions
To regain access to all the vertices of your trash can, you need to test different resolution strategies that address the possible causes of the problem.
Non-selectable vertices in Unwrap are like locked doors in your own house: you know you should be able to access them but something prevents you
- Apply Reset XForm before the Unwrap UVW modifier
- Check and unify normals with the Normal modifier
- Try different mapping methods besides planar
- Collapse the stack and start from a clean editable poly
Alternative Methods When Nothing Works
If after trying all conventional solutions the problem persists, there are more advanced techniques that can help you regain control over your geometry.
Solving persistent bugs in 3ds Max is part of developing your resilience as a 3D artist 🔧. Every technical problem you overcome not only allows you to complete your current project, but equips you with valuable knowledge to face similar challenges in the future, making you a more experienced and resourceful user.