The following applies to Rhino WIP using Direct3D.
It’s more or less the same with OpenGL, and it’s the same in Rhino 8.
There is a file with ~300000 flat curves.
The display performance is excellent when zooming etc..
But not when the curves are selected.
Or when we select one curve by a single mouse click.
The video shows the effect using TestMaxSpeed:
Unselected: 2sec.
Selected: 43sec.
I wonder why yellow elements take so much longer to display?
We can feel the lack of speed when we select an element by mouse click.
There is a notable delay until the element is yellow on the screen.
1sec.
And it takes the same time when we unselect by click into nirvana or ESC.
Makes me think the identification of the element is super quick, but not the display.
When I try the same geometry in Rhino 1.1, select/unselect has no delay at all for a single element.
It shows in yellow immediately.
(The general display performance of V1.1 is of course not on the same level as in V8/WIP - no wonder.)
@jessesn says it’s because the sheer count of objects.
300k curves isn’t that much!
Rhino 1.1 show the reaction w/o delay.
Rhino 8+WIP feels and is slow in this regard.
This is a DXF V12 Lines+Arcs:
2025-12-04_Yellow.zip (9.8 MB)
Also see:
And how Rhino 1.1 feels:
I wish I had it, too.