Q:

Subdivision Topology : Cut Triangle into Plane

I have a simple plane of quads, and I am trying to cut a triangle into the plane (using sub-division).
I can kind of get it, although I end up with triangles, and it feels hacky.
I want the end result to be a plane with a sharp triangle cut into it. Any suggestions, or pointer to resources of how to cut various shapes using quads and sub-d? (I havent had much luck with google).
Example of what I am currently doing:
Triangle in Plane

A:

https://topologyguides.com/ is a cool site that explores all sorts of topology issues.  
First of all I'd try to align the edges of your triangle with the grid of the plane.
The rest of it depends on what the rest of your mesh needs.  If you just need a flat plane with a triangle cut out, I'd do something like this and take those extra verts straight out to the edges:

that's all quads except for the two triangles on the left and right sides.  It subdivides relatively well with just a little pinching at the corners:

if you don't want to extend all the way to the edges of the plane you can keep the edges relatively clean but close to the triangle:
:
It still subdivides ok, but a bit more pinching, and is more triangles and fewer quads:

There may be a better way, but this works for me. Definitely check out the link to the Topology Guides site, though, because it's a fantastic resource. 

