I'm pretty new to Houdini so I imagine I'm missing an obvious key piece to this puzzle:
I'm trying to simulate plunging water waves rolling along a grid.
Imagine a set of water wave cross-sections built from nurbs curves that are skinned to create a wave front.
Now I want to take this nice single wave front and ‘merge’ it into an existing undeformed ‘water’ grid. This is also not just a height field approach. I have geometry curving over onto itself as the wave plunges.
So I have to carve away the geometry that exists in the foot print of the wave surface and stitch in my wave shape.
I've tried this a number of different ways and can't figure it out.
The closest I've gotten is using the Paste SOP. Unfortunately the trimming it does doesn't correctly match the curvy profile of the wave shape. It seems to trim only on a grid. I don't understand that.
I've also imagined using a Project SOP to get an accurate trim profile but that doesn't work straight from my wave shape.
If anyone undestands what I'm shooting for and has some ideas I can explore I'd appreciate it. Thanks.

Not a lot of takers out there, huh?
Okay, well I did make a small amount of headway:
I discovered a switch in the Project SOP that does now correctly trim the base grid to the profile of my bulgy wave shape.
However, I'm still a bit stuck on merging the bulge shape into the static grid. That is, adding appropriate polys, etc, to create a connected surface.
I've played with Join, Stitch, and Fillet but they don't simply fill in the gaps in the trim hole.
Any thoughts?
I think I remember seeing an example of something like this on one of the helpcards…

hi
are you building this after surf's up paper?
i did it also in houdini but i used curves much longer nad with higher point/cv density
so my wave lofted surface has lots of flat area beside wave…
z

Yes! I'm trying to follow in the footsteps of Surf's Up and get some nice breakers.
I'm curious: what are you using for wave shape profiles? Just draw your own curves based on what looked good?
I think I know what you mean about your extended wave shapes. That sounds like the way to go.
Perhaps we can join forces? : )

hi check this
I plan to finish and shade this properly
for now its just a sketch…

How about starting from this instead. The dark blue carve sop is your master control for the progression of the wave across the surface. The second carve is there to display the rest of the water surface and delete the surface under the wave. And it's important to have “preserve shape” on in the Skin sop since the wave is not actually attached to the surface.

Just to expand on this a bit more; the advantage of using the carve to control the wave is that your wave will behave correctly based on the width of the base of the wave.
As a wave approaches shore and the water gets shallower, the base of the wave has to stretch out (get wider) as the wave attempts to maintain its period. When the base stretches the wave gets taller.

its a nice setup , how do you plan to animate curves sequence for changing and traveling wave?
z

If you are asking me, I would animate the points on the profile curve to determine the curl. I'd animate the master carve to control travel and base width and then animate the mountain sop which will change the surface of the water and the wave. I'd likely change to alligator noise as well.
Then I'd depend on displacement materials to refine the water surface.

Thanks for the ideas.
That carve technique is a pretty good way to get the wave form merged back onto the static water surface.
However, is there any way that it could accommodate a non-straight wave front? Seems the carve approach demands that there's a linear wave front, huh?

Carve follows the u,v domain of the surface. You can modify the u,v's before the carve and get a none-straight carve.