Could somebody provide a link to the Blender documentation or another source, where (non trivial) select operations are explained? I mean performing intersection or union using all available select tools like Border or Similar.

  • Note: The question is not about using Border to add or remove rectangles. This is about Intersection or Union.

For example: I have selected the faces based on their material, but now I would like to keep only what is inside the green rectangle. I don't know how to do it, and I cannot find that in the documentation (currently learning Blender).

Screen capture

Usually graphic applications have select helpers like Intersection or Union to combine successive basic select operations. In my case I assume it's possible in Blender to intersect my current selection with a rectangle using Border.

Please don't provide shortcuts only. Using Blender 2.7. Thanks.

  • 2
    $\begingroup$ AFAIK this isn't possible directly (unfortunately), but instead you could: Deselect everything (A), select everything in the green region with box select (B), hide unselected (Shift H), deselect all (A), then do whatever it is you did to get the selection shown in your screenshot (Select by material or similar?). The operation should only select visible geometry, so when you unhide (Alt H) you should end up with the result you want. $\endgroup$ – gandalf3 Jul 2 '15 at 23:40
  • $\begingroup$ Thanks for the suggestion. I used the deselect as a bypass. Used Border + Drag LMB + Shift while releasing LMB. Did that twice to remove the non desired areas. $\endgroup$ – mins Jul 2 '15 at 23:57
  • $\begingroup$ As far as I am aware the linked question answers your question of wanting to "keep only what is inside the green rectangle". This is done by subtracting from that selection using box select. If I have misunderstood your question, then please add more details to your question, describing how it is different. $\endgroup$ – Ray Mairlot Jul 3 '15 at 12:35
  • $\begingroup$ Ah ok, you didn't mention multiple materials in your question, I would suggest adding it in as an example as at the minute you seem to be mainly mentioning removing from a selection. $\endgroup$ – Ray Mairlot Jul 3 '15 at 13:07

Unfortunately, selection tools don't support this directly. However, there are ways to accomplish the same result. For example:

  1. Deselect everything (A)
  2. Select the vertices you want to "intersect" with the previous selection. In your case, the vertices in the green rectangle.
  3. Hide the other geometry (⇧ ShiftH)
  4. Do whatever it is you did to get the initial selection that you want to intersect (e.g. select by material)
  5. Create and assign a vertex group to store the selection
  6. Unhide everything (⎇ AltH) and deselect (A)
  7. Select the vertex group by clicking Select in the vertex groups panel.

enter image description here

However in most cases like yours the desired selection can easily be obtained with one or two box deselections. To deselect with box select (B), use MMB MMB or hold ⇧ Shift when defining the box.

enter image description here

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