Selecting all objects inside a mesh

Question

Is there a quick way to select all objects inside a mesh? For example, I have a 15x15x5 grid of cubes. How would I automatically select all the cubes that are inside the toroid-like mesh object?

Update:

Weight Mode:

Torus Settings:

Answer 1

Since script is not here so one handmade tech. using Dynamic Paint from Physics Properties. Tested with official 2.82

• for Torus add Dynamic Paint as Brush
• Join Cubes Ctrl+J, add Dynamic Paint as Canvas > Surface Type > Weight and in Output click "+" icon if "dp_weight" is marked red. When you switch to Weight Paint mode you can see all Cubes placed inside Torus are red.
• Apply modifier for Cubes

When you switch to Edit mode you can see weight color as well if you enable Viewport Overlays > Vertex Group Weight.

• To select red cubes go to Properties Editor > Object Data > Vertex Group > Select
• Because some of the cubes were selected only partialy, you can select whole these by Select Linked Ctrl+L.

Notes: If you need Cubes separated back, just press P > by Loose parts.

(In experimental 2.83 I have some glitches in 3Dview editor > Weight Paint mode, but weight is visible from XYZ axis.Probably some personal issue with graphics card, because on Eevee mode Blender crash totaly.)

Just for fun ...

Answer 2

Depends on how you scene or objects are structured as you can select by Parent, Color, etc.

One of the easiest ways is to put all the smaller cubes into a collection (or collections of collections) and then selection is easy by right clicking on the collection and click Select Objects or Shift+ G -> Collection.

Another way I have used is to select by material. That is, assign the same material to all your similar objects and then select by Material: Shift+ L -> Material.

All of this takes a little bit to set up, but once done, selection is easy.

Answer 3

I would press A and then shift+ click to deselect one