Why so slow?

[11179]

Hey guys, I have encountered a situation where a simple definition makes Rhino and Grasshopper almost unresponsive.

The component move makes calculations here for 400 ms, but redrawing of “virtual” grasshopper geometry takes about 15 sec and vastly slows down everything for further manipulations.

I’m surprised to see that such a simple definition is redrawn for 15 sec. Could you tell, please, what may be the matter?

simple def.gh (12.3 KB)

[siemen]

See if this helps, I tried moving everything to the origin. For me it gives quite a difference.
simple def2.gh (17.0 KB)

[11179]

Indeed, it works! Thanks, Siemen!!!
When I tried to move my geometry further from (0;0;0), Grasshoper became slower. Do you have an explanation of such phenomenon?

[siemen]

I had the same question on another topic the other day.

@siemen

Interesting. Just out of curiosity, what is the logic behind this? Can you explain why this happens when it’s far from the origin?

Here’s the reply I got with a few links that explain the mechanics behind this.

Odd result with booleans on closed polysurfaces

This has to do with the way that Rhino 5 creates display meshes. Rhino 5 uses single-precision floating point numbers for these - Rhino 6 uses double-precision. A lot has been written here on the topic. A few links:

[stevebaer]

Graphics cards only operate in single precision (there are exceptions in very modern OpenGL, but for the most part this is just how GPUs work.) When geometry is very far from the origin, we have to perform a lot of extra work to massage the data into a format that will display well on your screen.