# Mask used to create a shape's shell **URL:** \ **Category:** Tips, Tutorials and Help\ **Created:** [January 5, 2025, 12:25pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939 "2025-01-05T12:25:12Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Angelo\_Salamini](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/angelo_salamini/32/25355_2.png) [@Angelo\_Salamini](https://forum.nomadsculpt.com/u/Angelo_Salamini)\ **Post date:** [January 5, 2025, 12:25pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/1 "2025-01-05T12:25:12Z")
Hi all, I’m new to Nomad Sculpt. I try to create a shell on a dental model using the mask function. When I have to extract the masked part the thickness is very wrinkled but the internal surface coincides with that of the model. If I use smooth function instead, the edges are smooth, and the internal surface enters the inside of the model. Are there any suggestions? Tnx for help Angelo ---
**Author:** ![RogerRoger](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/rogerroger/32/33580_2.png) [@RogerRoger](https://forum.nomadsculpt.com/u/RogerRoger)\ **Post date:** [January 5, 2025, 3:31pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/2 "2025-01-05T15:31:57Z")
Can you post a pic of your Extract settings? ---
**Author:** ![Angelo\_Salamini](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/angelo_salamini/32/25355_2.png) [@Angelo\_Salamini](https://forum.nomadsculpt.com/u/Angelo_Salamini)\ **Post date:** [January 5, 2025, 4:05pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/3 "2025-01-05T16:05:40Z")
Thank for answer ![Screenshot_20250105-170326](https://europe1.discourse-cdn.com/flex005/uploads/nomadsculpt/original/3X/d/e/de4afd578de469dcfd678ba41f0922562db73eb5.jpeg) ![Screenshot_20250105-170340](https://europe1.discourse-cdn.com/flex005/uploads/nomadsculpt/original/3X/7/9/79127d3346e8058424f2cc51db0f207c72404238.jpeg) ---
**Author:** ![Holger\_Schoenischka](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/holger_schoenischka/32/3934_2.png) [@Holger\_Schoenischka](https://forum.nomadsculpt.com/u/Holger_Schoenischka)\ **Post date:** [January 5, 2025, 4:43pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/4 "2025-01-05T16:43:58Z")
Maybe this helps. ---
**Author:** ![RogerRoger](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/rogerroger/32/33580_2.png) [@RogerRoger](https://forum.nomadsculpt.com/u/RogerRoger)\ **Post date:** [January 5, 2025, 5:15pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/5 "2025-01-05T17:15:51Z")
@Holger_Schoenischka did a great job of explaining. Better than I would have 🙂 One thing though- don’t forget a cement gap. If you don’t create one, your part will be too intimate and won’t fit without adjustment. If I’m doing something like this, I create two mask extractions: 1. Cement gap 2. My normal extract that I will sculpt on and create the dental appliance with. I either subtract the Cement Gap from my sculpting model, or if the Cement Gap extraction is nice on the external face, I’ll just mask it and extract from there for my dental appliance. ---
**Author:** ![Angelo\_Salamini](https://dub1.discourse-cdn.com/flex005/user_avatar/forum.nomadsculpt.com/angelo_salamini/32/25355_2.png) [@Angelo\_Salamini](https://forum.nomadsculpt.com/u/Angelo_Salamini)\ **Post date:** [January 5, 2025, 5:48pm UTC](https://forum.nomadsculpt.com/t/mask-used-to-create-a-shapes-shell/18939/6 "2025-01-05T17:48:18Z")
Thank you so much. Clear and inspiring. For cement gap/tollerance I’m following the same Roger ‘ssteps. For undercuts some solution? Here the mine (not too clean) Differently I remove undercuts and close model in meshinspector and the I import model in nomad Regards