Losing material when creating block

[robM]

Hi,

 

I'm trying to create a simple 3d object, similar to a a piece of steel box section. I can create the shape, apply the materials, but when I create a block, the material just disappears. It only appears to happen when I'm creating 'hollow' shapes - normal simple shapes work just fine. Have I missed something?

 

This is how I create the shape...

 

In 2d viewed from the top, I create a 300 x 300 sqaure. Then I ofset the sqaure by 10 inwards to create a box within a box. I then extrude each by 500 and then use the subtract command to remove the centre section.

 

When I switch to 3d view, I get a something which looks just like a piece of steel box section. This is just what I want. I then apply a material and it looks fine. but... when I create a block, all of the material then disappears and I'm left with a drawing which looks like I haven't applied any materials at all.

 

I've tried using the union & intersect command just before extruding, and just before I apply the material, but I still get the same problem when I convert to a block.

 

It's a really simple shape, so I'm sure there is a simple step which I'm missing. I'm quite new to working in 3d, so any help would be gratefully appreciated.

 

Many thanks

[MikeScott]

I assign material by layer, perhaps that would help here?

[robM]

Thanks Mike. Still getting the same results I'm afraid. Seems like it can't recognise what faces it needs to render, so it doesnt bother. It only happens when i convert to block and only affects objects with holes in which I've created using subtract. - box section, tubes and the suchlike.

Solid objects are fine.

[robM]

Think I've got it. Wasn't using the region command anywhere to create a single object before applying the material. I guess that's what happens if you just skip past bits in the tutorials thinking they won't matter!

[Hoozin]

That's an awesome thing to learn and I'll have to keep it in mind, but that's a weird little quirk. Thanks for posting the answer, I feel like this is a question that may come up again.