Hi,

Recently experimented with some pop/dop stuff (driving particles with fluid, in particular), I hit another “Houdini quirk”.

After I spent about an hour to reproduce an example scene (from exchange, I think) I realized that the POP solver in dopnets can't “import” popnets from SOP networks (the kind of popnet which has 4 inputs). The other type of popnet (the general one, without inputs) works fine from any other network.

Now this is something I call annoying (the sop-popnets are my favorite ). Even more, if you're new to Houdini (such as myself), this can be quite confusing (and I got a few years of CG technical experience, so it took just a half an hour to pinpoint the problem, but what about a real newbie? ).

This is not the first time I ran into such a thing – it would be useful to have a document or a web page describing such ‘quirks’ (not checked odforce yet).

Such things may not get noticed by the hard-core users anymore (as they learned to ‘live with it’, I suppose), but can be quite boring for newcomers.

(I could also talk about some chopnet evaluation ‘strangenesses’ and the like – most of the cases I can ‘guess’ how the architecture works and understand the way things work – or doesn't )

imre

The POP solver is able to reference any POP Network SOP. You just have to use it exactly the way you would use it in SOPs.
Explicitly set the source geometry in the Input Geo folder to the SOPs actually feeding in to the POP Network SOPs four inputs. That way you avoid any object transforms.
If that is not the case, please post the file.


Any CHOP update issues would be considered bugs so please report these.

An example of CHOP strangeness: we have a quick Maya->Houdini exporter, which exports Maya transform data as .clip files. These files then read by a CHOP in Houdini, and applied to the objects and camera (this way you only have to update the .clip files when animation changes in the Maya scene).

Now, let's say one CHOP exports its data to the camera, and I want another CHOP to fetch the same thing from the camera and use it somewhere else. So far I haven't got any luck with this – sometimes it worked, sometimes it didn't. Results were inconsistent.

I guessed that the root of this problem might be that there's no explicit execution order for the various CHOP networks (the one that ‘puts’ the anim on the camera, and the one that fetches it), so it's kind of understandable. (I don't mind if it worked properly, though )

I'll check again the POP thing you mentioned, but I'm pretty sure it didn't work (I spend at least half an hour with it).

riviera
Now, let's say one CHOP exports its data to the camera, and I want another CHOP to fetch the same thing from the camera and use it somewhere else. So far I haven't got any luck with this – sometimes it worked, sometimes it didn't. Results were inconsistent.

I guessed that the root of this problem might be that there's no explicit execution order for the various CHOP networks (the one that ‘puts’ the anim on the camera, and the one that fetches it), so it's kind of understandable. (I don't mind if it worked properly, though )

It should all be based on dependencies. That is if there is no recursion going on.
What you describe should work and in the two test cases I just worked up I could not reproduce. It all worked…
What version of Houdini are you using?

Granted I have experienced update bugs with CHOPs in the past. If you have a case that breaks it, please send that in to support.