STEP import

I created an addon to import STEP directly into Blender.

Information on the old & free version

Depending on what operating system you are using, you can delete the modules (.dll = Windows, .so = Linux, .dylib = Mac)

So far tested only on Windows 64-bit. You can also download the SDK from for your OS if it’s not working, and copy the Python module from that into the addon folder.

Addon creates UV based on CAD surfaces, also creates automatic smooth/sharp in an attempt to make the model look good. There’s also an option how high polycount you want to make the model better approximate the base CAD model.

The location is in the import menu.

I rewrote the entire thing from scratch again with OpenCASCADE. It should now work much better. As it’s quite a bit of work, I also set a price and created a new version on Gumroad. The old one is still free. If you got the free version before this update let me know if you didn’t also get the OCC, so I can send you a free copy as a thanks for the interest. Note: it currently supports only STEP, no IGES.

If you have any comments, let me know.

How to report issue

Copy & paste the following: import platform as p; import bpy; "|".join([p.machine(), p.platform(), p.python_version(), p.python_compiler(),,]) into Blender Python Console and tell me what it prints out, in addition what your issue ie. Use the email address you got from your receipt from Gumroad and send the message there, using the email address you used to buy the addon.


Nice! This might prove to be very useful when a client needs to deliver CAD models for rendering / work in Blender.


I work a lot with CAD data so this could be interesting to try out.

First of all, this thing should not be $0 as a base price. Closest comparisons I have for this would be Power Translator for Modo and MOI3d. I guess it depends on how far you want to take the addon.

I’ve dropped some $$ to you on Gumroad to show that there is some interest but I really hope you take this further.

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Sure what kind of things would you like to see?

Some sort of progress bar or visual feedback would be great or even an estimate of the poly/vertex count. MOI workflow would be on the export side obviously but it give you a slider that basically adjusts the curvature angle like you have there and it converts per object gradually as to not make the machine unresponsive for a period.

Yeah, getting hole fidelity right without cranking the polycount is tough.

I would like to see better individual objects, but I’m not sure how much of that is a limitation of the file format.

Again, not sure if this is a limitation of the format, but instanced objects would be much appreciated.

This is an amazing job ambi !
It will be very useful, because I think you made the only STEP importer for blender.

Looking over GMSH docs, it seems to be capable. Maybe more of these features should be exposed. I used to use Netgen for the same purpose.

Fist of all nice work ! I have been wating for a CAD Importer for ages. I have tested it so far with some free online step files and it seems to work. But using files from my client (Autocad / Solidworks) crash all the time. Sometimes choosing another model makes no difference, it just loads the exact same as before with the same settings. Is there any place where I could leave you the error messages / non confidential files ?

Also I would add .stp to the accepted file formats, did that in the init and seems to work fine. Or is there any reason not to ?

filter_glob: StringProperty(

The filter is already changed. It will be there in the next version.

You can send me links to error messages and files you want me to test in private messages or even post it in this thread if you want to.

Hey ambi- very very useful work. I think this will be awesome for industrial design concept work. Its been a bit of a workaround to bring in OBJs from moi3d. This way we can at least stick with blender to bring in internal components and reference geometry. This is nice- although it would be nice to have the stp brought in natively and re-tesselated on the fly- or if there was a way to trigger a re-import by clicking on the imported meshes. Is there any way to import normal maps from the CAD geometry? OBJ imports from moi3d and Solidworks have a normal map that cleans up the highlights and reflections. The highlights here at lower resolution were squirrely. Shown below- Test STP file in moi3d.
Imported STP in Blender and remeshed using Quad Remesher. Thanks!

Quad model from Quad Remesher.


I will rest this tomorrow bed time now !

Started Testing mechanical shapes using this link:
MIxed results- for some reason STP export from moi3d was not recognized, but iges worked. Import hanged on the stp from grabcad- exported out one of the legs and was able to bring the iges into blender.
as some noted before it takes a while to think through more detailed surfaces- and missed some of the iges closed surfaces.


Seems like there is the sweet spot that I have yet to determined wrt level of detail that this addon is designed for. The first image shows the CAD file that I am trying to get into Blender. Only IGS import was visible to Blender. Some parts did not make it through- It did a surprisingly good job on the Plus geometry in the buttons that did make it. Remeshers, in general, don’t seem to do very well with detailed CAD. These seem to work with simpler models.


I made an update. The entire thing is written from scratch and should work a lot better now.



I’ve posted a message about this at the MoI 3D forum:


There was an issue of missing files. STEP_OCC_import_0.0.7-REPACK is now up that should fix those issues.

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Wow-what a difference in a day. This alternative version works much better for bringing in the CAD files to Blender. Does OpenCASCADE allow ngon and quad output?