Locate undercuts on tooth model

I have a model of a tooth. My goal is to see undercuts when looking from above the tooth. I am currently using a “wrapper” called JSModeler. If you looked directly down onto the biting surface of the tooth, I would like to color all the surfaces that you can’t see from this vantage point. Additionally, I would like to measure the depth (horizontal-depth of undercut) of selected areas. This is an STL model.

My current approach is to use raycaster (directly from above) to locate multiple intersections, marking the side of the tooth where the ray exits (through the bulge), but that is slow and not that accurate.

Do you have any suggestions for an approach? Ideally the undercut surfaces would change color as the tooth is tipped back and forth.

Hi David
I have much experience in 3d Dental project using threejs , webgl
I already have built similar function project for my prev company

I would like to discuss more details directly
Telegram : @DSODIN
Discord : DS-3dworld#0020

I would like to hear from you. Are you free to talk?

Yep , i m available for discussion now
we can take a interview
What is your email address?
I will send google meeting link if you are available now
Thank you

How about zoom or phone?

Zoom is fine

You may email me directly at lee@dbkx.com

thanks i will invite you soon