First off, I'm very new to houdini and thus far haven't done much more than watch some tutorials. I know that I can create a group by selecting some points but what I'm hoping to do is create more of a parametric group. So what I'm trying to do is take a cylinder that has 24 sides and select two loops of edges, skip an edge loop and select two more until I've worked my way all the way around the cylinder in this pattern. Check out the attachment (done in modo) for an illustration of the type of selection I'm trying to create. But I'd like to make it so that if I change the sides from 24 to something more or less it will keep the same selection pattern. I'm sure this is doable in Houdini, but not sure how. Can anyone suggest how? Thanks.

check this file
this is not a great way to do it - but it should help a bit
Houdini edges are not real entities - so they don't have an index, you can't do any fancy selections with them

HTH

arctor
check this file
this is not a great way to do it - but it should help a bit
Houdini edges are not real entities - so they don't have an index, you can't do any fancy selections with them

HTH

Ok, I'm trying to break this down so I understand what's going on. As I said, I'm brand new to houdini, so please let me know if I'm incorrect here.

In the first group node you've created a group named topbot and enabled edges. I'm assuming this feeds all the edges into the 2nd group node named sides. In that you've set up the group by range with start and end of 0 and $N. I'm not clear on what this (0 and $N) does. Then select_of set to 1 and 3 so it's selecting the first and third edge?

And that selection is sent to group3. I see that your operation is happening in the combine tab, but again I'm not sure what it's doing. Can you explain this at all? Thanks so much for the help!

group2 node - I'm making an edge group by determining the Max Edge Length
so this grabs all the short edges - the ones on the top
group1 node - I'm grabbing 1 out of every 3 faces, then on the Edit tab I'mm converting this group of faces to edges
group3 node - now on the Combine tab I'm making a group called ‘edges’ that is NOT the topbot group AND the sides group.

I should have named the nodes properly :\

HTH

On this particular example, you can get away with “just” two nodes. (See attached example).
I select 1 of 3 faces, convert them to edges then remove the boundary edges in the second node.

Obligatory: Any chance we will get edge indexes, attributes etc. in the near future? Like maybe in Houdini 16, or so? :wink:
- Even if the edges are not entities on their own, SideFX could make their use easier, by imposing a superficial system that internally works with vertices or whatever. The productivity boost for users would be significant…

can't say/don't know specifics but better/proper edge support is something that is high on our list