[OpenSCAD] eval( ) ???

Torsten Paul Torsten.Paul at gmx.de
Thu May 14 13:27:16 EDT 2015

On 05/14/2015 06:58 PM, Carsten Arnholm wrote:
> Sidenote: One thing that has struck me is that the compilation
 > in OpenSCAD is quite fast, but the rendering (F6) is extremely
 > slow. I was wondering if the generation of triangles for STL
 > really needs the graphical rendering to be completed first? If
 > not, one could imagine a function to export the compiled model
 > to STL and use an external viewer to speed things up when iterating
 > on a complex design that takes forever to render.
No, F6 being slow is mainly due to the CSG processing in CGAL.
While the OpenGL rendering itself is badly in need of improvement
(or should at least get additional support for GPU based rendering)
it's not the biggest factor in most cases.

Preview (F5) is fast as there is no CSG happening on mesh level, but
it's handled by OpenCSG using clever OpenGL rendering.

STL export needs the fully generated mesh which is generally not
available after just doing a preview.


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