ExtractSrf not able to select through front surfaces


#1

I use ExtractSrf to pick surfaces out of polysurfaces so they can be assigned to different layers. Think of a table top with laminate and and edge moulding. I want to extract the top and bottom surfaces from the polysurface. I can pick the surface that’s visible, but not the one behind it. This used to work in Rhino4, but now I have to rotate the view around to pick the 2nd surface.

It’s not a big deal, but it’s slower. Instead of clicking the poly twice to get the front and back face, I have to click-rotate-click. Is it supposed to work this way now?

Using Version 5 SR6 32-bit
(5.6.31009.7465, 10/9/2013)


#2

I can repeat your problem only under the following circumstances:

  1. The object is an extrusion object
  2. The object has surface isocurves turned OFF

If i turn isocurves ON under Properties / Isocurve Density, it is possible to select the occluded surface once the surface in front has been picked. (If the object is an extrusion). For polysurfaces, i´m able to click the occluded surface even when isocurves are OFF. Tested in Shaded and Ghosted display mode.

c.


#3

Clement,

I’m seeing the same thing here. Polysurfaces seem to work correctly, extrusions don’t.

I also noticed something weird testing this with simple boxes: A box made with the box command is an extrusion object. A box made with bounding box is a polysurface… Why would anything that wasn’t extruded be an extrusion?

JT


(Pascal Golay) #4

Hi JT- lightweight extrusions can be used to represent objects that are linear in one direction at least and have planar curves defining the profile- that is, if they could be extruded from planar curves or faces, they tend to be made as extrusions. BoundingBox could also use extrusions, it just never got done, I guess.

-Pascal