Rhino 6 moves simple mesh 19 times slower than Rhino 5

The following file holds one simple mesh. I used gumball to move the mesh by short distance. Rhino 5 moves the mesh in about 2 seconds. Rhino 6 moves the same mesh in about 38 seconds.
slow mesh bug.3dm (255.6 KB)

Ah, you mean displace.

Yeah - Here, if displacement is on, and a view shaded, any transform operation is slow in v6 for sure.

Oh, I see that YT went to David E, not Andy …


That is ok, they can tomorrow fight over it in the office.

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Is that entertaining at all? Is there any office pool on picking winners in these things?


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I’ll propose that tomorrow…

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I used rendered display mode and custom texture on the backfaces.

Rhino 6.1 (2018-2-6) moves the same mesh in about 34 seconds.

I have experienced similar sluggyness. (I can’t bug track that right now, just wanted you to know that you are not alone in your observation )

Hi @Andrew_Nowicki, this is another symptom of a known issue. In Rhino 5 finding a good Initial quality setting used to be tricky because document absolute tolerance was involved in the displacement quality calculations. Therefore we removed the effect of absolute tolerance in Rhino 6. This is why result of displacement in some V5 models is different in loaded into Rhino 6.
The solution is to turn down Initial quality setting in Rhino 6. In your model Low produces results comparable to Rhino 5.

Initial quality setting of what?

In the Displacement properties of the object:

Changing displacement mesh quality reduced the time to move the mesh with the Gumball (in Rhino 6) by half.

If you want it to go faster you can disable Max faces setting.

It cuts the time to 4 seconds - twice as long as for Rhino 5.

Another cause for slowness: displacement is done twice when dragging. This wasn’t the case with Rhino 5. I’ve logged item for this too: https://mcneel.myjetbrains.com/youtrack/issue/RH-44375

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Rhino 6.3 moved the same mesh in about 43 seconds. Displacement was turned on. Initial mesh quality was set to medium. Max faces was set to 1000.

We know. This is logged as a bug. At the moment, we’re trying to figure out how to fix it.