I've tried solving this problem for a couple of days and I suspect there's a simple solution that I'm missing.

The attached image is a top view of a room which can be considered a box basically. I want both porches (points 80-83) to extrude outward, only one does so atm.

If I group the two bottom edges opposite each other and polyextrude, the extrusion front will be at a 45 degree angle since it's the average normal direction. But I want to extrude the porches outward and horizontally.

So I figured out that attributes might be the way to go, so I created an attribute forward and gave it value (1, 0, 0). But as you can see in the image this only means both extrude the same direction as expected.

So can I somehow account for the normal direction when creating the attribute or can I transform the attribute to local space or similar? Perhaps I'm making this way to difficult than it should be.

not sure how you created your holes (porches) first…before extruding….if you delete to create holes THEN extrude…that could create screwy extrusions…

Rather, just select the prims to be porches, extrude them, it will use the existing FLAT faces for the extrusion…THEN delete to get the holes after.

I did this this way and it works absolute fine..

so I tried on edges, they still extrude out correctly and not inwards like yours…but of course the bottom edge would be angled rather than straight because of the normal…but who would select the BOTTOM edge to extrude for the porch ? makes no sense at all…

Thanks for your replies. The first idea about extruding the face might work, I didn't consider it since the goal is to create a nice doorframe later on (attached image). But I suppose extruding the face, then delete the parts I don't need is a viable option.

Regarding the other post the motivation was that it seemed easier to get the right geometry later for the door-frame and such after I've extruded a porch/balcony.

I managed to solve it late last night by simply copying the distance parameter of the Polyextrude and pasting it as a relative reference on the extruded front so I translate it based on the distance extruded.

It's a bit weird but it works nicely at least. Maybe I should consider your first post more though, it just seems more involved to extrude the face then delete a bunch of faces, then Polyfill the holes. Not sure what's the best way as I just started learning Houdini.

Btw if anyone has any ideas on how to select adjacent edges that would be awesome. As you can see in the first picture I just select the edge that belongs to the door - it would be cool to select an adjacent edge to either the left or right and extrude a larger porch/balcony but I have no idea how atm.

edit: I found a way to select adjacent edges. I used the Group-node and expanded by edge-depth - then used Group Combine intersect with the walls bottom edges. This solution selects adjacent edges to the left and right of the door-edge, but I have no control if I want to choose either left or right - I always get both using this method

not sure I understand correctly, but if you just want to extrude in a custom direction, you can provide that as an attribute