Help with Halo-like energy field?

[alksndr]

In a lot of games they seem to have an effect like this and I don't think I've ever seen it a movie vfx reel so I want to do it in houdini and add some more complexity to it.

 

Heres a ref: http://3.bp.blogspot.com/-XuXWF0hepnI/UBrIcFH-BuI/AAAAAAAAGC4/QOHBK121Y_k/s1600/img_3089_halo3teaserstill.jpg

 

So the idea is a particle beam or something hits this invisible area on a sphere, and from that point the effect will spread to the other side. So particles stick to the surface and spread across. To make it tougher I wanna make it dent and deform the geometry a bit where the particles are spreading, and also be able to be hit from multiple points. But right now i'm still struggling with the basics lol so I'll attach what I have.

 

The hip file is noise in vopsops spreading over a sphere, the first issue I run into is figuring out how to spread it from a point I choose. Right now its all happening everywhere at the same time. Heres an image so you can see where im at in a render, just as a test: http://i.imgur.com/QDNaL37.jpg

 

Heres a playblast of my attempt in maya, got a bit further along cuz I can make it animate outwards from the top but  want to know how to do this in houdini plus add the manip of geo

 

Any help would be appreciated, I guess the biggest problems here right now are a lack of understanding of vop sops to get it to behave and animate the way I want to, and then somehow using that particle information to dent it.

 

Thanks guys.

shield_bad.hip

Edited September 12, 2014 by alksndr

[Robert]

You can try specifying the hit position and then calculate the distance from all the points of the sphere to the hit point. 

You can use the distance value as a sort of mask when you create an animated threshold for it (compare node, dist value > Frame*value).

This should at least give the feeling of the effect spreading from the point of impact.

[mightcouldb1]

Quick example

halo.hip

[mightcouldb1]

You can transfer attributes by intersecting with a plane

[alksndr]

You can try specifying the hit position and then calculate the distance from all the points of the sphere to the hit point. 

You can use the distance value as a sort of mask when you create an animated threshold for it (compare node, dist value > Frame*value).

This should at least give the feeling of the effect spreading from the point of impact.

Damn sorry but I don't really know how to do any of that. I see that I can select the point I want using a sort on a scattered sphere, but everything after that is idk.. Can you give me a file or some more explanation about how to do that?

 

You can transfer attributes by intersecting with a plane

 

That shader is sick!! So the transfer attributes can be a replacement for the vop sop noise i see, i can create that similar kind of moving down thing from anywhere now.. But I still can't delete the stuff I don't need to see. I have a black sphere and red grid right, so I want to delete all the red points. I feel like I saw it was $CR>1 in the delete but its not working for me?

Edited September 12, 2014 by alksndr

[Robert]

I made an example with a pointwrangle. 

You can replicate pretty much the same thing inside a vopsop but this was just easier to do.

 

I made a small mistake in the comments in the point wrangle.

Instead of "This will refit the noise from 0 to 1 to a smaller band that travels across the sphere" I meant that it refits the distance attribute to a small band.

energyshield.hipnc

Edited September 12, 2014 by Robert

[alksndr]

I made an example with a pointwrangle. 

You can replicate pretty much the same thing inside a vopsop but this was just easier to do.

 

I made a small mistake in the comments in the point wrangle.

Instead of "This will refit the noise from 0 to 1 to a smaller band that travels across the sphere" I meant that it refits the distance attribute to a small band.

 

You the man. Thank you. Its awesome. I'm gonna check out the wrangle workshops and learn more about all this. 

 

Now just gotta figure how to map this color to opacity, or delete by color, and then also deform by color. Thanks again!