Motionfx and Copy Node

[jsells20]

Hello, so here is what I need help with.

1. I have a walk sequence that has been copied, with a copy sop.

2. What I want is to have the "shift" and "stretch" motionfx to randomize each copy.

3. I'm not sure what expressions go where to control this.

4. After I get a randomized min and max for each copy, I want to be able to have each one follow individual curves.

5. That way I could do a follow path on my obj and have the next copy jump to that curve.

How would I do this, what type of expressions would I use and where?

*I tried to use the rand and fit function for scale in the "stretch" motionfx with .02 range values and I keep receiving .2 values. I need it in the .02 area.

Edited April 30, 2013 by jsells20

[rafaelfs]

You'll need to apply your chops to the character prior to the copy SOP and use a stamp function to randomize the channels imported for each copy.

It's not hard, there's probably something already posted here, but if not I could whip something out for you later.

Cheers

[jsells20]

I applied the motionfx before I put in the copy SOP for the character.

I put this into variable 1

variable name: scale

value: rand(stamp("/obj/s1/motionfx/fx_shift/scroll", "scroll", 2))

Nothing. I don't think I'm doing it right. If I want a min and max value randomization, wouldn't I be using the fit function instead?

~~~

I need this done for the motionfx scale (stretch node) and scroll (shift node) to vary my copies.

Then I'll need to be able to have each one go on a curve. Or, have each one able to be animated by the master control separately. Right now the walk cycle is in place.

I've looked around but I cannot find much info on motionfx and copy stamping.

If you have time today to do an example, I would be eternally grateful.

Edited May 2, 2013 by jsells20

[rafaelfs]

Here goes a simple example...

Cheers

chop_copy.hip

[jsells20]

I have some questions.

My character has a lot of controls animated, 37 to be exact. It's not from a single transform.

My motionfx is outside in the main network, not within the geometry, if that makes any difference.

I only have a channel, shift and stretch node for the motionfx as well. Do I need more?

What is the math node doing in the example you have?

Am I able to apply this to a stretch or shift node? How?

You have two channels, why?

Mine just says 37 and a list of the channels below. I only have 1 channel node.

Edited May 4, 2013 by jsells20

[rafaelfs]

I have some questions.

My character has a lot of controls animated, 37 to be exact. It's not from a single transform.

a) My motionfx is outside in the main network, not within the geometry, if that makes any difference.

b)I only have a channel, shift and stretch node for the motionfx as well. Do I need more?

c) What is the math node doing in the example you have?

d) Am I able to apply this to a stretch or shift node? How?

e) You have two channels, why?

Mine just says 37 and a list of the channels below. I only have 1 channel node.

a) it only affects the path to your chop network when referencing it somewhere else (like the channel SOP) or exporting;

that is up to you, if all the channels can be stretched and shifted at once and the animation still looks fine, then yes;

c) math CHOP is copying the imported animated channel onto the new channels I created within the chop network;

d) you mean the workflow? I suppose so... you'll have to figure it out though cause I can't say without looking at your file;

e) The first channel imports the animated channel into the CHOP network, the second one creates one empty channel for each copy of the sphere I want to place.

You only have one channel node because you are only stretching and shifting the channels for the one character you created. Optionally you can use a stamp expression to randomize the value of the stretch and shift within the chop network. that would actually be much simpler...

Cheers

[jsells20]

I just made a digital asset and imported each into the scene, then applied the motion effects to them individually. I feel like I have more control over doing it like that anyway.

I would like to know how this is done later though, to be able to add the effect to a lot of copies, like birds or something. Seeing that I only need about 3 copies in 1 of the scenes, taking this copy route does not seem necessary.

If you know how to do this, I would like for you to look at my file.

Would it work best to post the file here or email you later?

Honestly, I still don't understand how to set this up. I kind of get the general basis of what to do with your example, but nothing concrete pops to mind. I'm fairly new to the procedural arena too, but everything else in Houdini I'm comfortable with.

Let me know if you don't mind looking at the file at a later date.

Edited May 10, 2013 by jsells20

[rafaelfs]

Sure, post the file here and I'll look at it when I've got some time...

Cheers

[jsells20]

Ok, thanks! I've uploaded an older file with a rough animation. I didn't add the clutter of where I was experimenting with the motionfx and copy node. The bgeo is in the zip too.

jsells20.zip

Edited May 10, 2013 by jsells20

[jsells20]

So I've done some research and found this. vimeo.com/25336681

I haven't done a crowd sim before in Houdini and I can't seem to find much info on the topic.

Do you have any good reference links or examples?

My end goal is to start thinking more procedural to make a behavior for an array of spiders.

Edited May 29, 2013 by jsells20

[rafaelfs]

Sorry, man, been really busy and with not time to look into your files...

Here's what a quick search resulted:

https://vimeo.com/30333203

https://vimeo.com/53087785

There's also a nice tutorial on flocking at CMIvfx.

Best of luck!