How to make corners sharp and square or triangular openings in Sub-D

I’ve been trying to figure out the best way to get square corners and triangular or 4 or more sided openings in sub d seems like a lot of trouble currently.
I’ve looked at some of the solutions but was hoping for more definitive answers.
See attached file.
Thanks for any tips and hints.
Sub-D_How to make corners and openings Sharp.3dm (60.9 KB)

Hi @3dsynergy
Start by looking at the Crease command - it’ll let you add creases to edges and vertices. As for the triangular or n-sided openings, look at InsertEdge and InsertPoint. See the help file for details :slight_smile:
HTH, Jakob

Crease (vertices)

Thanks Jakob definitely helps.
I’ve been playing with crease it works on this simple example but seems bound to failure in others. I’ve attached the file where I tried to create a triangular window and crease does nothing and so does insert edge. Also I’m finding these weird display artifacts at the corners of the opening in the attached file, seems not correct to have these maybe a bug?

I’m trying to find a workflow or know the steps to produce sharp corners and openings in any sub-d. Seems cryptic at the moment on how when and where to add extra edges to get there.

Sub-D_How to make corners and openings Sharp_002.3dm (56.4 KB)

Thanks Inju, take a look at the next example I posted to Jakob I see display artifacts in the corners and I can’t achieve a triangular opening using crease or insert edge.

You need to learn the rule of creating topology.

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Hi Inju,
Thanks for your help and for pointing me in the proper direction! Your quite right that’s why I was asking for the proper way I’m glad I posted that second file, I missed the earlier discussion where you posted the table chart and links to proper topology.
Thanks again for your help,

For me it helps seeing the mesh as 3D controlpoints for the surface, like controlpoints work for a degree 3 curve.

So if you want a box with rounded edges you will need 3 points in each corner (two mesh faces). The smaller they are (the closer the controlponts are for a curve) the sharper the corner.

That’s how I plan my patch layout anyway :slight_smile:

Here are a few examples for you:
Dark lines are creases.


Thanks Holo much obliged for your postings.

Hi Holo!

Do you have an example for how you would adjust that on an edge where it is split or open? I see how this works with closed surfaces or adjacent surfaces, but what about for an edge that I have unwelded? There is definitely a crease all along the edge, but I don’t see any options to change the edge type.

edge question.pdf (227.3 KB) subd test.3dm (84.2 KB)

keep in mind, you can always get it close in subd, then convert to nurbs and do the rest there… just because you have a new hammer, not everything is a nail…

use the best tool for the job.

subd = soft and sculpty
nurbs, sharp and precise.
mix them appropriately= modeling awesomeness