Hi,

Maybe a silly question, but I have this geo tree model without any groups.

How can I select/group/separate the tree itself and the leafs without too much hassle, so I can assign materials to both separate selections?
I found some old threads on grouping via quad/non-quad selections, but they don't seem to work anymore.

It's probably a simple one, but thanks for all tips!

rob

If your trunk consists of quads only and your leaves of triangles, you could put
in a group expression node.

Hi,

Found the group expression node as well, after some searching.

What about selecting via points or edges?
It seems more useful as one can drill into the geo model to delete small parts and merge it all back later.
Cannot seem to find examples on this atm in the docs :\

rob

edit: tree + branches are mostly quads and some triangles, leafs are quads and triangles.

In primitive selection mode, right click and choose “select n-Sided Polygons” might help ?

Hi,

Back at this one. ;-)
As explained before I have a tree model with no groups, where the tree/branches are made out of quads, and the (flat) leaves are a combination of quads and tris.

To start extracting the leaves, I can select the leaves with a group node, and set it to select ‘unshared edges’.
This will select all the leaves, as they share no borders with other primitives.
From there I can promote the group from edges to a primitive selection.

Only issue here now is that the open end/edges of the branches/tree are moved over to the primitive promotion.
So I have the leaves selected, but also the start primitives of the tree and branches.



There's an option in the grouppromote node to ‘Include Only Elements Entirely Contained in Original Group’.
But when I check that, it's doing exactly the opposite of what I expect, removing everything from my group selection.

In older versions, this would remove the open bordered edges, thus bordering primitives from the selection, and keeping the closed primitives sets (leaves).

Has this node behavior changed in later versions of Houdini?

thanks,

rob

Not sure if this is the right solution, but perhaps converting from edgesgroups to points and then to polys ( with contained components options ) may help ? Can you upload your file ?

Hi,

The additional step did the trick.

So it's group the edges, promote it to points, promote it again to primitives. In the second promote you can check the ‘Include Only Elements Entirely Contained in Original Group’ to get rid of the ‘stray’ elements in the selection.
Now I can easily split the model into separate pieces with a couple of blast nodes, and add materials.

Thanks for the extra nudge in the right direction, as I have some more trees like this model.

rob

anytime.

BTW, just realised. This is Houdini .. just replace the input Geo and the rest is automated. Or merge all of them and pipe that into your network…

Half the time I go to other apps and start missing Houdini.

Yes,

I already packed it up and created a little tool for it.
And you're right, the freedom in Houdini to do things makes other 3D apps feel very restricted at times.
But I still miss some (workflow) things from Softimage to make it even easier to work with.

rob

XSI