Hi there,

I am filtering the copy node to only copy to points with an attribute above a certain value and it seems to be working but I feel there's probably a better way, could someone have a look at this and see what you think?
I just have a feeling I am over complicating it.








Here's the scene -
http://www.peterleary.com/ForumFiles/FilterByAttribute-kwRgeT1VLf.hiplc [peterleary.com]

Thanks,
Pete

What you have does work, but you could reduce all those nodes down to a single wrangle.

vector freq = {1,1,1};
vector offset = {0,0,0};
float amp = 1;
int turb = 5;
float rough = 0.5;
float atten = 1;
float NoiseSelect = fit11(onoise(@P*freq - offset, turb, rough, atten) * amp,0,1);
if (NoiseSelect > 0.5) {
setpointgroup(0, “CopyFilter”, @ptnum, 1);
}

no group necessary, just keep your VOP that creates the attribute
then in Copy SOP's Template Group write
@NoiseSelect>0.5

Thanks for posting the question, its threads like this that really help in moving over to vex

Rob

That's great, I had no idea you could get that all in a Attribute Wrangle node!?

I think I'll stick with the Point Vop and the template set to @NoiseSelect>0.5.
Since I'm really new to Houdini, the Point Vop interface is a little easier for me (and it reminds me a little of softimage ICE).
Also if it runs a little slower that's okay since I'm FBX-ing all of my work out for unity.

Thanks guys!

VOPs and wranglers generate the same VEX code so no worries about performance.

Both will run at the same speed if they generate the same code at the end.

Use VOPs to learn and get going and to build proper first class assets for further re-use later on.

Wranglers are just a convenience for TD's who just want to “wrangle” some attributes quickly without diving in to VOPs to construct a network.


Many times wrangle code gets out of hand where VOPs makes more sense for portability and learnability imho.

So Jeff , basically the rule of thumb is if you can create your data in vex wrangles or attribute vops , you should. ie

if (@Cd.r >= 0.5) {
setpointgroup(0,“grp_isred”, @ptnum, 1);
}


Is going to be faster than actually creating the above in the group SOP .

Rob

there is no guarantee that VEX will be faster than native operators, you better test it for every case (in case of Group SOP by expression, VEX seems to be faster though)

on the other hand setpointgroup() will probably be slower than i@group_ at least for heavy geometry since it's not multithreaded
so if you want to create group from attribute in VEX instead of using ad-hoc groups, you rather use:
i@group_grp_isred = @Cd.r > 0.5;

Agree with Tamte.

Test every case with the Performance Monitor when fine tuning performance of critical networks. All TD's should be well versed in the use of the Performance Monitor as an important debug tool.

Clarification on wranglers. Most wranglers are placed directly on top of a VEX node so in most cases, my statement should be a good guide to use VOPs and wranglers.

In some HDA assets that have wranglers at the top level, there may be other non-VEX based SOP types inside the HDA asset that will break my general comment above.

Again always test when performance is critical.