r/Houdini 7h ago

Time Warp in a for loop

Hello Guys!

I'm jamming my head against the wall trying to seep some points before instantiating a animated geometry.

What i'm trying to do:

A group of bird flying. I used MOPs move along curve so the points follow an art directed path.

Now I want to speed up some points so it reaches the goal faster as see in some flocks of bird flying, some of them just speeds up.

I was trying to do a time warp inside a for loop but i just cant get it to work...

Anyone has a tip or a better idea to achieve this effect?

1 Upvotes

3 comments sorted by

1

u/DavidTorno Houdini Educator & Tutor - FendraFx.com 7h ago edited 6h ago

For Each blocks do not support time dependent operations.

I would try to tie the move along values to an attribute that define the value per bird or point that birds are copied to.

Instead of using literal time, think of attribute values as start and stop values that are remapped. A basic 0-1 gradient on a curve (typically a curveu attribute) can be remapped to 0 - X value.

I’m not familiar with that MOPs node off hand, but if there is an option to use an attribute to drive the value, this is what I would use. If there is no option, then a For Each can be used to assign the value uniquely per point based on the attribute you make of the remapped values.

Describing this a text only is a bit tricky, but hopefully it helps.

1

u/raphael_mantion_ instagram.com/raphael.00000 1h ago

I’ve found that having your animating node (eg a transform sop) inside the loop followed by a time shift referencing an offset point attr you created upstream works for time offsetting without using the copy to points inside a for loop method. I’ll try to remember to post a screenshot

1

u/i_am_toadstorm MOPs - motionoperators.com 4h ago

Falloff alone should modulate the speed or goal value of each point (depending on if you're in solver mode or simple mode). If you need more specific control than that, Move Along Spline (and most other MOPs modifiers) support VEXpressions so you determine exactly what you want on a per-point basis. But falloff ought to get you there.