Import Polygons from GDS



We often need to import polygons from GDS which have many vertices (>1000). This is very common for silicon photonic layouts, where polygons can be Manhattanized to meet certain DRC rules. However, the current version of the softwares (MODE/FDTD/DEVICE) does a very poor job displaying such polygons. The software gets extremely slow and hardly usable after importing the gds. We have to close all view windows to be able to click on any buttons or type anything in the script editor.

Can you please fix this issue in future update for all softwares? I believe the fix can be done by simply showing just enough points based on the current window resolution and zoom-in ratio. The softwares are really painful for us to use when it comes to actual GDS layouts. Looking forward to a better version.

Drawing structures with rounder corner in FDTD

Hi @senlin

I am sorry to hear that you are having difficulties with poor resolution and slow performance. Can you please upload your GDSII file so that I can take a look at it?



Hi. The problem I believe arises from the visualization of the geometries. You can try to reduce this problem by switching to the “wireframe” render mode for the imported polygons.


Thanks for your reply. I tried, unfortunately it doesn’t help much. The software gets stuck right after importing gds, which makes it difficult to even navigate to the window you showed here. A default render type needs to be set beforehand. I can provide a gds example for you. Could you please give an email address? Thanks.


Hi @senlin, can you try this:

  1. Close all the visualization windows first (XY, YZ, ZX, and Perspective view).
  2. Now import the GDS polygon. Since the visualizer windows are closed, hopefully the system will not slow down a lot.
  3. Switch to the “wireframe” render mode for the imported polygon.
  4. Enable the visualization windows.


with regards to this problem, i have also experienced similar problem - slowness + laginess when i import large GDS with polygons of many vertices (>1000)

May i ask: if a higher RAM / graphic card /CPU may improve the slowness and laginess?
May i know what is a graphic card requirement for good seamless fast display of gds with lots of polygons and many vertices?


Hi @hongwei_gao

Unfortunately increasing RAM and GPU will not solve the issue. Using a higher speed CPU might improve the problem, but will be minimal. This improvement is requested by our customers in IX which you can vote on and our team is investigating the problem and looking for a solution:

As a workaround, I would suggest to use a lower resolution and move to finer resolution as last simulation step. Some of the recommendations in this post such as using wireframe might also help.