[OpenSCAD] a matter of speed....
arnholm at arnholm.org
Tue Jul 16 14:28:32 EDT 2019
On 16.07.2019 14:18, Doug Moen wrote:
> The GPU isn't used for rendering. What does speed up rendering is a large CPU cache and fast RAM. For example, see this old forum thread, where benchmarks are used to prove this: http://forum.openscad.org/OpenSCAD-performance-numbers-td4707.html
> Multiple cores helps, but I think this is model dependent, since I don't think that multiple cores helps with the final top level union.
> Lots of RAM is a good thing, it allows you to render larger models.
> Doug Moen
I tried the bracelet example in that link on my Kubuntu 18.04.2 LTS
machine with 32 GB RAM & 4 CPUs, running openscad_nightly 2019.03.31
For some reason openscad_nightly is rather limited as it can only read
files under ~ (i.e. /home/username). It can't even see my second disk
where I usually have things like this.
That aside, the bracelet example from the old thread ran in 15 seconds
on my machine. The old 2013 thread reported times of several minutes.
The model created seems fine although it looks like OpenSCAD reports the
wrong number of faces generated, it reports 7816 faces but the real
number seems to be 8400 faces/4200 vertices.
At the bottom of the gist I recreated the same example using AngelCAD
(v1.3-01) which does multi-threaded processing. With a bit of tweaking
it also creates 8400 faces/4200 vertices in 1.51 sec, i.e. 10x faster.
This is a small model, so the top level union issue is not really
apparent. It is true that if multi-threading is done per boolean
operation, the final operation will run on once CPU only and will not
benefit from multiple cores.
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