Maxxing out GH Performance

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Permalink Reply by Chris Wilkins on December 15, 2009 at 11:12am

I have no answer, but I'm adding to the question...

I've been curious lately as to which GH components are memory intensive. For example, I use Pipe a lot, but as soon as I pipe, things get wretchedly slow. Does the slowness occur in GH, or in OpenGL? I'm guessing for Pipe, it would be an OpenGL slowness. But then take a component like Planar Surface - I'm assuming that this component would be doing more complicated work inside GH (or in the SDK beneath?). So will certain components always be slow for GH to calculate, and will certain objects always be slow to render in OpenGL?

Permalink Reply by David Rutten on December 15, 2009 at 11:33am

Significant time is spend in four areas:

1) Grasshopper canvas redraw. I'm optimizing this, but especially ParamViewers with loads of paths inside and the Compass widget take a lot of time to draw. Drawing speed here depends mainly on the speed of a single processor. Get a faster processor, increase the redraw speed.

2) Geometry operations. Such as Piping, Lofting, Curve CP etc. These are all performed by the Rhino core so there's little to be done here. We're continuously working on speeding things up, but they're already pretty fast (considering the complexity of the tasks). Rhino 5 has got a few bits and pieces of multi-threaded code and once we're convinced they're working well we'll probably apply those newly won skills to other parts of the core. These operations are also dependent mainly on processor speed.

3) Autosave operations. Since these involve writing data to the disk, it's very hard to predict whether or not it will be a fast or slow operation.

4) Viewport previews. This code is actually pretty horrible, it could be much faster than it currently is. However, a good Graphics card will make a lot of difference both now and in the future.


The ideal spec for Grasshopper is the same as it is for Rhino:

A) Get a good graphics card. We no longer shun ATI since their latest cards are actually pretty good, so either get a high-end NVidia or ATI card. Good gaming cards are not necessarily good CAD cards. Gaming cards are optimized for triangles and sprites, they don't do particularly well with curves.

B) Memory is dirt cheap, get as much as you can. 4GB being the absolute minimum. But, be sure to get fast-access memory, makes a lot of difference.

C) Get a fast processor. Since neither Rhino nor Grasshopper very much use multi-threading it is important that every single core is fast. I.e., don't get fooled by vendors who add the core speeds together and present that as the processor speed. One core running at 4 GHz is better than 8 cores running at a combined 16GHz.


As for OS, I'd recommend XP Pro or Windows 7. Stay away from Vista if you can. Also, almost all the software and hardware problems I come across at workshops are happening on MacOS machines running some flavour of Windows. Be it parallels, Bootcamp or VMWare.

--
David Rutten
david@mcneel.com
Poprad, Slovakia

Permalink Reply by Chris Wilkins on December 15, 2009 at 12:51pm

Thanks for the in-depth knowledge.

I think I'll use my current machine as a paperweight, or maybe target practice...

I'm still on Rhino 4. Should I get Rhino 5? (I thought there was some incompatibility with GH at some point)

Permalink Reply by Marc Syp on December 19, 2009 at 12:57pm

I've been running Rhino 5 off and on for a while now... there used to be some display issues with GH and OpenGL, but those have been fixed in Rel. 0043 and I haven't found any bugs in RH5/GH that aren't in RH4/GH.

Marc