# Square - Octagon - Circle - Modelling puzzle

I'm trying to make a rubber mat that is basically a big flat cube with lots of little holes (cells). It makes sense to me to model each cell and use an array modifier to construct the overall mat.

The problem I'm having is one i frequently run into in other areas too, which is how to add geometry as you go along without creating shading issues.

In this particular example, I need to go from a square outer edge (4 verts) to an octagon (8 Verts) into a circle ( I can get away with 16 verts). I've done this by a combination of extruding and subdividing, which works okay(ish) but generally creates shading and edge loop issues.

My question is - Is there a proper way to perform this kind of extrude and subdivide modelling? Or am I going about it the wrong way completely?

Many thanks in advance!

Sam

## 2 Answers

in my opinion you are going fine, remember that there are many ways to achieve what you want in Blender, so in this case I see two other possibilities.

Option one:

You can add the flat base geometry.

Select and erase these vertices

Add a mirror modifier like this

And then extrude

Option Two:

Use Boolean

Add a cube

Add a 8 vertices cylinder

Add a Boolean modifier to the cube like this

To look the cylinder in wireframe only, go to Object menu > Display > and set Maximum Draw Type to Wire

Repeat the previous steps with the other geometry, at the end you will have something like this

Now when you're ok with the look, just apply the modifiers and done.

• Thank you for such a helpful answer! I'm going to give them both a go right now - I really like your viewport shading setup by the way Dec 18, 2018 at 16:13
• For the viewport shading press N and a new menu appears, go to Shading > enable Matcap > enable Ambient Occlusion Dec 18, 2018 at 16:16

You could do it this way:

• Create a plane, subdivide it 5 times. Create an octogonal circle, subdivide it once. Duplicate and scale down this octogone and make it a circle with W > LoopTools > Circle.
• Join the vertices of these shapes with the help of W > LoopTools > Bridge.
• Extrude to have a 3D shape.
• Give it a Subdivision Surface modifier and a Bevel (Weight) modifier so that it makes the circle smooth but keep the angles of the octogone sharp.
• Add your Array modifier, put it above the Subsurf modifier and enable Merge and First Last options, so that it joins correctly between the duplications.