Dissolve edges

[twisted]

A problem I’ve come across in trying to create the door frame.

Thought I’d make the inner & outer surfaces first like this

and the fill in the ‘front’ & ‘back’ faces.

and then, to minimize the geometry, dissolve the additional circled diagonal at each corner.

At first my plan seemed to go all right, but when it came to dissolving the unwanted diagonals, after working for the first two, the process stopped working.

the third and fourth diagonal refusing to dissolve.

Are there some edges that cannot be dissolved?

[Capricas_Kirito]

There are some edges your cant dissolve. As a general rule you want to have 3 or 4 edges for every face. In the images above the optimum is to have a diagonal edge at each corner of the door frame but, if you are really set on minimizing geometry, you can reduce to 2 diagonal edges, set at opposing corners. Getting rid of too much geometry will compromise your ability to work on the model at later stages and can adversely affect the UV Unwrap when you go to texture the model.

[twisted]

Thanks for that.

May I leave aside the issue of what’s going to cause me problems later on, and explore what’s possible?

Deleting the 3rd diagonal would leave a face with either 9 or 10 edges depending on if the remaining diagonal were counted once or twice.

Is that even possible? That is, a face where a single edge is used more than once.

[Capricas_Kirito]

In theory, it sounds reasonable that you would be able to get down to just a single diagonal cut. However, in practice, the complexity of the face you are trying to make determines the minimum number of cuts you will have across that face. I’ve never looked into the mechanics of vector graphics so I can’t explain the reasoning behind it. Perhaps Michael or Marc can give a better answer

@Marc_Carlyon

[Marc_Carlyon]

@Michael_Bridges I know it does it but having issues with formulating it into an explanation short of it needs those edges to create that face.

[Michael_Bridges]

I think the limitation here is not the number of edges but the fact there is a hole in the middle of the ngon. I’m not sure of the underlying code that calculates the ngons however!

[Michael_Bridges]

Yes, done some further reading, it’s not supported.

[twisted]

Thanks for your help guys.

That’s interesting. I’ve been trying in various different ways to create a face with a hole, but no matter how I try and sneak one in, blender won’t let me!