How to group polygons with more than 4 points?

[blackchicken]

Hello, sorry for that question but I cant find it somewhere. I saw that somewhere but my head , I starting modeling titanic for little project at work, and I want model as much procedural as I could. I want model it in maya, but, why not houdini? so I have main body, There is a lot lot of little windows. I choose projecting circles copied on line. But triming create little artefact. So I choose polygons and cookie, works great. I create bounding group(for polycap), add polycap, but there I want little radius in windows for speculars to add measure of trunk. so I need extruding capped polys(12 ngon) how I could procedural select it? I mean, group polys with more than 4points Thanks a lot for help.

P.S.: Is there some easy way how to cup holes in mesh? I mean no groups, in maya I select model, choose hole, and maya automaticaly fill all holes. Houdini needs selected boundary edges or selected faces. (If I could get automaticaly group of new polygons, cups, will be great). Thanks BC.

[graham]

The key is that you want to group any faces that have more than 4 vertices. Since there is no expression that gives you the number of vertices for a polygon in hscript, you can either do it with a simple python expression, or using Attribute Promote. In the attached file there are setups doing this.

Using a python expression, you can compare the number of vertices for the currently iterating primitive and group if there are more than 4.

len(pwd().curPrim().vertices()) > 4

Or you can create a vertex attribute, set the value to $VTX + 1, then use an Attribute Promote to promote it from being a vertex attribute to a primitive attribute using the Maximum method then use that attribute to group by.

group_num_vertices.hipnc

[Serg]

The key is that you want to group any faces that have more than 4 vertices. Since there is no expression that gives you the number of vertices for a polygon in hscript, you can either do it with a simple python expression, or using Attribute Promote. In the attached file there are setups doing this.

Using a python expression, you can compare the number of vertices for the currently iterating primitive and group if there are more than 4.

len(pwd().curPrim().vertices()) > 4

Or you can create a vertex attribute, set the value to $VTX + 1, then use an Attribute Promote to promote it from being a vertex attribute to a primitive attribute using the Maximum method then use that attribute to group by.

$NVTX > 4 works too

[graham]

That was what first came to mind, however for some reason my current Houdini build isn't playing so well with that so I had to suggest alternatives

[Serg]

That was what first came to mind, however for some reason my current Houdini build isn't playing so well with that so I had to suggest alternatives

Oh,

Dont have houdini in front of me so cant test it here right now.

[graham]

sigh. Further testing shows that the development build I have seems to have issues with local variable highlighting for lots of stuff. The first thing I tried was $NVTX > 4, but when I typed it in it came up red and I was like "Am I imagining that NVTX is a variable?". I should have hit Enter anyway since it works, even thoughn the input field saying it is invalid. I feel like a fool.

[blackchicken]

perfect, thanks a lot

$NVTX > 4 works great for me, cool little trick