Surface vs Mesh Bounding box

[hanparker]

If I create a mesh from a surface and compare bounding box - they’re usually the same (or very similar). However I have a problem with a particular surface and mesh bounding box that don’t match at all.

The surface bounding box is:

-484.928, 306.161, -2.153 -461.052 369.464 -1.080

The mesh bounding box is

-484.750 318.537 -1.711 -464.764 330.983 -1.360

This is if I GetBoundingBox in code. If I draw the bounding box manually in Rhino it matches perfectly…the Surface bounding box co-ordinates seem to be the ones at fault after manually checking.

I am using the GetBoundingBox(true) option for both the mesh and the surface.

Usually this code that compares the mesh BB to surface BB works fine when match meshes and surfaces so I am confused as to what is happening here. Any idea?

[Willem (Willem Derks)]

Hi Hannah,

See if this post gives someinsight:

C++ boundingbox - how to get tight?

Today I was trying something I thought would be super simple. Draw a sphere, select it with a command, get the BREP and get its bounding box from C++ code. I tried .BoundingBox(), .GetBoundingBox(…), .GetBBox(…) an .GetTightBoundingBox(…). None gave a true bounding box for spheres that were not centered to the origin. Are there any examples on how to do this correctly?

-Willem

[hanparker]

A lovely - thank you. I’ll have a look at that.

While I was messing around I found that I think it was caused by the surface being split. I recreated the surface from some lines that were split rather than splitting the surface and it no longer had the issue.