Some defects after extrude

[MrCedric]

In fact the point is simple, the « cnc guy » needs a correct file. The step and the obj/stl/dxf preview has to be correct too.
The curve in FreeCad is smooth with no angular lines so the visual proof (obj/stl…) has to be the same.
Unfortunately even if in sharecad its better, but the preview still show facettes and triangular contour. So it doesn’t match with the FreeCad preview.

[drmacro]

The cnc programmer is not using the rendering of the surface to program. He/she will be using the mathematical definitions provided in the step file.

He/she should not be using stl representation of the model either, since stl definitely is not intended as a cnc source geometry.

What you are seeing is an artifact of the render process and has nothing to do with getting cnc data.

At least...that's my opinion...

[jeno]

In fact the point is simple, the « cnc guy » needs a correct file. The step and the obj/stl/dxf preview has to be correct too.
The curve in FreeCad is smooth with no angular lines so the visual proof (obj/stl…) has to be the same.
Unfortunately even if in sharecad its better, but the preview still show facettes and triangular contour. So it doesn’t match with the FreeCad preview.

Detach yourself from the idea that you are looking in freecad at the mathematical exact description. Nope, you are looking at triangulated surfaces spruced up with some shading algorithm.
Remember you read about deviation and deflection in an former post from chrisb. Both steers how fine or coarse the approximation is.
When you directly export to stl or another mesh format you save the triangulated surface you see in the freecad window bit by bit.
Those online viewers has to be coarse because the should run on every platform from an old mobile or tablet to the most powerful computer.

Regards

[GeneFC]

The curve in FreeCad is smooth with no angular lines so the visual proof (obj/stl…) has to be the same.

Unless you are sandbagging us and showing a different object that is simply not correct.

Capture.PNG (1.38 KiB) Viewed 611 times

Those sharp interior angles cannot be done with ordinary CNC.

gene

[MrCedric]

The « cnc guy » wants a proof, to avoid any dicussion about the prototype, and it seems fair.
I can not sending something without it, plus without any confidence about the file, hoping it will be nice by magical, it is not serious

[drmacro]

The « cnc guy » wants a proof, to avoid any dicussion about the prototype, and it seems fair
I can not sending something without it, plus without any confidence about the file, hoping it will be nice by magical, it is not serious

Then just send a wireframe view, then the rendering is taken completely out of question.