Hi @Michael.Weber 

Thank you for reporting this. I can confirm that this is an active bug report which is currently in the hands of our developers. Are you able to share an example of the prism you are building? It will be helpful to know if you are using Coordinate Breaks, Tilted surfaces, or some other method to generate the slanted faces. 

If you are more comfortable sharing a privately, feel free to open a case with us here: Profile – Zemax.

I will be sure to post a reply to this post when there is an update from our developers. 

Hi Allie,

thanks for your answer!

The prism is constructed using coordinate breaks, I attach a small screen-shot. 

Michael

Hi Michael,

Did you try disabling the Use ACIS option and see if the CAD export works fine that way? You can do so in the Setup tab\Project Preferences\General. If so, then this might be an issue with the ACIS libraries for CAD export.
It’s hard to say what might have caused the CAD export issue just based on the screenshot. Would it be possible for you to share the file with us so our developers can take a look? If the file is proprietary, you can either open a support ticket with us to share the file privately, or you can create a dummy file that demonstrates the issue so we can look into it. 

Best,

Hui

Yes, I did try to disable ACIS (as mentioned in the original post) and that does solve the problem. But as it took me a long time to find out about that option, I thought I should report it.

There is a simple prism example on your webpage using surface tilts, not coordinate breaks. I tried that, and it shows the same behaviour.

I attach the archive from your webpage, I used the simple file “Single Prism.ZMX”.

Kind regards,

Michael

Hi Michael,

Thank you for sending in the file. 

Yes, currently if you turn on the Use ACIS option, the CAD export may not work properly exporting beam splitter made using CBs. This is a known bug in the ACIS libraries for CAD export. Our Development team is aware of this and is working to resolve the issue.

Thank you for bringing this to our attention and we’ll keep you posted if there is an update on the issue. 

Best,

Hui

Is there any news from Zemax on this topic? Recent versions (ZOS 22.1.2, v31 ACIS) still show the same behaviour.

I am mostly fine with turning off the ACIS libraries, but now discovered that the STEP file is much cleaner with the ACIS option enabled. So it would be really great to have a workable solution with ACIS enabled.

best regards,

Michael