Trimmed NURBS surfaces

[ms35]

Hi everybody,

I am wondering, if it is possible to do trimming of NURBS surfaces with FreeCAD without losing the properties of NURBS surfaces.

I have two IGES files with several NURBS surfaces inside. The task is to trim the surfaces from the first file with the surfaces of the second file and vice versa. The result should be several IGES files with the grouped surfaces, so the files with the desired trimmed surfaces can be processed further. I know it is mathematically a hard task to do trimming on NURBS surfaces, but eventually somebody already had the same problem and have done some work on this topic.

At the moment I use SolidWorks surface trimming, but it is really painful (freezing GUI, manually selecting surfaces, etc...). Also automating the task via a Python script would be great for my workflow.

Thanks in advance

[Cekuhnen]

Surfaces in CAD are easy to trim - this is nothing special.

FreeCAD can do it while the workflow and tools it offers are quite different than what most users know from other packages.

For example FreeCAD has no trim untrim tool.

But Part Workbench has many surface commands one could use.

Use the slice Slice Apart or Boolean Fragment command
And then sort out the not needed surfaces.


And then you export as STEP.

[Rongjiang]

Dear Mr,
May I contine to this question? I have a similar problem.
I have successfuly trimed my surfaces using Boolean Fragment command and export it as IGS or STEP format. However, I can't find a cross line of any two surfaces when I opened exported file, if one surface wan't timed into two pieces. That is to say, if a surface has been trimed into two separate pieces and export IGS format, we can find the cross line along the intersection of two surfaces; however, if a surface has been partly trimed by another surface, and actually get a line on the surface, we can't see it when we import this IGS format file. So do you know how to conserve this line when a surface has been partly trimed? I am looking forward to your responds. Thank you.