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I am trying to make hollow cube something like this: hollow cube in wood

I am new to blender but I would have thought that this should be straightforward. I made a cube, and then a longer cuboid which I inserted in the middle and then used the Boolean difference modifier. I changed the orientation of the cuboid twice more to make the other two 'holes' through the object.

Since the operation seemed to go smoothly, I was surprised to see that the holes didn't cut right through the cube, and that in wireframe mode some artefacts were created:

cube enter image description here

I tried making both objects solid (using the solidify modifier with default settings), but even after making the first Boolean difference operation I can see an unexpected triangle in the model:

enter image description here

Could someone please advise me on what I'm doing wrong?

I am aware that for a simple model like this I could assemble it from cuboids, rather than using a difference operation. However, I would like to be eventually use the techniques to make more complex models for instance a hollow Dodecahedron. Therefore I keen to establish the correct way of making these hollow type models.

I am tempted to try making a new face for each side of the cube and extruding it inwards but I don't know how I would handle getting the inwards extrusions to join up with each other.

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    $\begingroup$ Why use booleans for such simple geometry? $\endgroup$ – Duarte Farrajota Ramos Mar 9 '18 at 13:09
  • $\begingroup$ Hi @DuarteFarrajotaRamos, as I said, I'm new to blender. If there is a more straightforward way, please point me in the right direction. The only requirement is that the technique should also be able to be used to make more complex items for instance a hollow Dodecahedron $\endgroup$ – Paul Trotter Mar 9 '18 at 13:11
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Option A subdivide all faces of a cube, select the middle edges then bevel them. Either extrude the large faces inwards, or erase them and use a Solidify Modifier. If the former don't forget to remove doubles.

enter image description here

Option B Just select all fates then use Inset > Individual Faces then *Extrude > Region (Vertex Normals).

enter image description here

Also works in icospheres. If self intersections are not a concern you can use a Solidify Modifier replacing the last extrude step.

enter image description here

Alternatively you can use a Wireframe modifier, for a slightly different geometry.

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  • $\begingroup$ Thanks @Duarte - really clear solutions. Option B worked perfectly for me. $\endgroup$ – Paul Trotter Mar 9 '18 at 20:04

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