Hi!
I ‘ve got two questions which can be helpfull not for me only as I supose, so if anybody knows the answer… (what happens not very ofen on this forum…unfortunately)

1. there is no tut. or detal doc about Rigid Body Dynamics on Sidefx webside or on “learning houdini” while it`s quite important issue… so if anybody knows any link or can write some tips. After lecture of POP RBDCreate doc I just can’t handle it. Lots of examples and tut. on POP works fine and I understand all of those - exept this one: RBD. So please help! I can't built a simplest RBD system with ball and floor.

2. Another question is more complicated: lets say we have sky dome or even simply grip over our scene, we texture it with some nice hdr. We make light instancing with this grid points… AND!!! WE WANT TO COPY TEXTURE COLOR from POINT POSITON to our LIGHT shader (approximation color of some texture area would be better but lets leave it now). Well, how to do it? Usage of that is obvious.
Is there anybody out there?

Best,
SYmek

so if anybody knows the answer… (what happens not very ofen on this forum…unfortunately)

Wow.. thats a sure fire way to get someone to answer your question. Try not to be too insulting right out of the gate next time, and you may get some people actually wanting to help you.

So please help! I can't built a simplest RBD system with ball and floor.

Lucky for you I just uploaded a file to od that shows basic rbd. Please feel free to download it and see how its done.

http://odforce.net/forum/index.php?s=14951d644b2b7c8cb9909bc4871b6aff&act=ST&f=21&t=1248 [odforce.net]


Cheers
Marc

Sorry for that beginnig, maybe its because of language… i didn't mean that evrybody here knows nothing about H. I only looked on cold numbers and they say what they say: not too many awswers for questions.

if anybody feels touched SORRY!

I think you'll find that there are so few answers here because the ones that are given tend to work really well….

yes, that's a clever answer
point for you.

Hello Marc!

Thanks for example of RBD, it really helped, it's so simple but if you don't know that you have to add chop op, system won't work - and that was my problem. So.. here is another: it looks like houdini computes rbd transformations in such a way that this data can't be pipe in to renderer since there is no motion blur in mantra or RMan. I suppose that I have to bake transformation and turn off rbg and applay chops to objects. Am I right? Maybe some examples… please.

best,
symek

If you use the viewport tools to create and manage your RBD system, it creates the POPs and CHOPs for you automatically. Best to use the toolbars and go to the generic tools (tab key works just as well). You can add force objects that add the appropriate object-pop association for you, wind, some constraints, etc. Best way is to try the options then see what POPs and CHOPs are added.

By the way, adding force objects and wind objects is a great way to get object control for any POPs.

Thanx!
Yes that's great tip! I've never worked like this, because working with nodes gives me filling of control over material whitch is nice. I see every step. On the other hand all SideFx tutorials seams to prefer different fashon of working since they almost always suggest to maximize viewport window.

Any suggestion on motion blur issue from previous massage?

best,
SYmek.

The motion blur issue:

It does work if you just set your motionblur setting in your ROP to “Transform” automatically. The problem is that the simulation takes a small step forward in time to determine where the blur should be going and then doesn't rewind after that step. This makes your motionblur occur only the first time you hit the render button until you play your simulation again. This is a bad quirk of the RBD system right now.

If you want more reliable motion blur, go to your CHOP network and set the method in the RBD CHOP to “Cached”. Now you can play your animation forwards and backwards and your motion blur will work all the time.

Hope this helps you out,
Jason