Meshes are wrong placed in block that has big base point

Hi everyone

I created some meshes and polysurfaces located somewhat far from the center of coordinates (-100000, 350000, 440000).
Next I tried to put those geometry into a block with very big base point (144000, 145000, 9000).
And then after block creation meshes (but not polysurfaces) were moved into another location within the block.

What is even more interesting is that I can’t select those moved meshes. But if I select an empty space where meshes were located first - the moved meshes within a block would become selected.

So it looks look Rhino thinks that meshes are in the old location.
I can reproduce this behavior when the document units are millimeters.

Does anybody has any ideas what’s the cause of such behavior?
Any help would be appreciated.
Thank you.

If you place the objects nearer to the World center (0,0,0) and create the block there and then move it far out, do you still have the same problem?.

The problem may be what you already indicated yourself, namely the distance from the world center, a distance that may stretch beyond what (internal data-) “number size” Rhino can handle within the precision settings.

// Rolf

Hi Rolf,
Thanks for the response.

No it looks like everything is fine in this case.

Also I played with base point values a bit. And it seems like polysurfaces work just well. But for meshes there are troubles. For example if I set the following block base point (100000,100000, 50000) - just one mesh from the example is moved. And the other mesh stays on its place.
So I’m just curious, why meshes move within a block depending on block base point value and distance form the center of coordinates while the polysurfaces stay on place as should be.

Meshes are stored as single-precision floating point numbers in Rhino 5 whereas surfaces (i.e. the underlying NURBS) are stored as double-precision floating point numbers. In Rhino 6, both are double-precision.

Hi Wim
Thanks for the replying

Interesting, actually this fact can explain the troubles I have.
But I installed the Rhino 6 WIP and I’m able to reproduce slightly different behavior: meshes don’t move to another point after block creation. They stay on place as should be or just dissapear :slight_smile:

Could you make a new post in the Serengeti category and include a 3dm file with your objects?

Sure, thanks.