Hello devs!
I’m trying to understand some logic behind POPs by using their SOPs counterpart as a reference.
In the current version, is there a way to replicate SOP bounding box function with the possibility to use an external reference? Or is it something that might be implemented in a future version?
Here an example of what i mean.
Group POP like SOP.toe (9.5 KB)
Hello,
The group POP cannot group using an arbitrary geo at the moment.
I’ll make sure it’s on our list of features to add.
One way that’s a bit convoluted is to use the ray POP and output the RayInside attribute, that tells if the point is inside the object or not (based on how many surfaces it hits), but not move the geo (scale on ray POP at 0) and then use the RayInside attribute with the group POP.
See attached
RayPOPBoundingObject.toe (10.2 KB)
A couple notes: currently they ray POP can be slow, it’s on our list to optimize it, and the extrude POP currently doesn’t allow to output the back face, though you need a closed surface for the above to work well. For some reason I wasn’t able to get a nice geo by merging the back face with the extruded bits, which I will look into, so I used the skin POP and merged and fuse the front, back, and sides together.
Modelling hasn’t been a big focus of POPs so far, so SOPs can still come in handy and you can bring them to POPs with the SOP to POP operator.
I hope that helps and let us know if you have other questions.
edit: took the liberty to edit subject since Bounding Box/Sphere is possible but not arbitrary bounding object
Hi Vincent,
thank you for the time you dedicated to sharing this example. It has helped me clearly understand some aspects of the ‘attributes’ process within POP.
Right, thanks for the reminder. I did that because I’m currently more familiar with how things work in SOPs, whereas POPs have so many attribute-focused options that I’m still getting used to.
Edit: I tried converting my group3 SOP into a POP to see if the group tags would remain, and I noticed that they do — but two new ones appear: ‘_sopptgroup_pointclosure’ and ‘_sopptgroup_primclosure’. I’m not sure if this is intentional or a bug.
Yes, indeed. If I just wanted to use a Bounding Box or Sphere as a reference for the POP group, is that functionality built into the operator? I didn’t notice it.
Cheers,
Edwin
Thanks for the report, that looks like a bug, probably groups used internally by SOPs that should be skipped during the conversion, I’ll take a closer look.
It’s there but a bit more hidden than in the SOP, on the bounding page you can choose Bounding Sphere or Box but you also have to select an attribute used as the position (maybe we should rename the label to make it more explicit).
GroupPOPBoundingSphere.toe (10.3 KB)
(added to previous toe I shared)
Also POPs currently don’t have guides the way SOPs do, though that’s on our list, above I used an Attribute POP to Color in red the points inside the group, I forgot there’s also a debug color toggle on the first page that will color differently points inside and outside the group.
Awesome, thank you!
