topic Re: unexpectedly closed solder mask in 3d-model in Fusion Electronics Forum

unexpectedly closed solder mask in 3d-model

dongli_zhang — Wed, 10 Dec 2025 18:14:28 GMT

Hello,

I'm working on a 3d-model for my PCB with a library of my customized component. The Footprint consists of a customized polygon on top copper and the same pattern on tstop and some border lines on dimension (picture 1). An SMD pad is placed on top copper to form connection. I expect the polygon part to be open on solder mask and the tstop was displayed correctly in PCB board interface (picture 2). However, when I switched to 3d model, the solder mask was not properly opened. Only the part on top of the smd pad was opened (picture 3).

I assume this was because I copy-pasted my polygon from top copper to tstop to have the same pattern on both layers, since I got the error in picture 4 when I did this.

How can I deal with this?

Thank you and have a great day!

Re: unexpectedly closed solder mask in 3d-model

jorge_garcia — Wed, 10 Dec 2025 19:54:35 GMT

Hello @dongli_zhang ,

I hope you're doing well. So first off, your 2D file is correct and is the source of truth for the design. At this moment in time the 3D PCB can't render all features correctly and this comes up most often for arbitrary pad shapes like the one you are working on. One thing you can try to see if it gives you the right rendering is to go into the 3D PCB settings and make sure Stop Layer Geometry is checked. Let me know if you continue to run into problems.

Best Regards,

Re: unexpectedly closed solder mask in 3d-model

dongli_zhang — Thu, 11 Dec 2025 16:17:12 GMT

Hi Jorge,

thank you so much and you made my day! I turned on 'Stop Layer Geometry' in settings and now the solder mask is displayed correctly!

Best regards,