Help with particles, newbie inside!

[Akabane]

Hi there! I have a few questions.

I'm using Houdini 10, and i watched the 3dbuzz's Tornado tutorials (houdini 8 maybe?).

I recreated all they did i was interested in (all but the shading part).

Now i was wondering a way to shade the particles; i thought i could create a volume from the particles, then shade it with a pyro or smoke shader; and that's what i did (via IsoOffset node). But the problem is that the volume doesn't carry on the velocity attributes i set up for the particles, so no motion blur or a good swirly-around-the-axis look. Tried couple ways but i wasn't able to do that.

Then i thought i could create a mesh from the particles, carrying on the v attrib so it would "stretch" in the way i wanted it to, and then shade it somehow. So I tried a particleFluidSurface, but no luck again. Still too blobby look and no good stretched look.

So that's the first question: any help? If i want to create that stretched tornado-cartoon-look mesh from the particles, or if i want to shade them with a fluid but having the "tornado" swirly feel?

Second question: i was trying to "convert" the particle SOPs into POPnets. Created popnet, source, damp, all good, but then i was encountering problems when using Orbit while trying to push them down with a Force. It seems that the Orbit goal always overrides the down Force. Why is that? How can i replicate the particle sop force? (Axial/Vortex forces?)

Sorry for the long post and if the questions are newbish, but i'm here to learn

Thanks.

Akabane

PS: (For the shading part, i also tried to render a i3d file, res 128 128 128), but it was rendering still after 30 mins, so i stopped. Any clue? I followed the guides from the "how to create clouds" from the houdini help)

[ragupasta]

Hi there! I have a few questions.

I'm using Houdini 10, and i watched the 3dbuzz's Tornado tutorials (houdini 8 maybe?).

I recreated all they did i was interested in (all but the shading part).

Now i was wondering a way to shade the particles; i thought i could create a volume from the particles, then shade it with a pyro or smoke shader; and that's what i did (via IsoOffset node). But the problem is that the volume doesn't carry on the velocity attributes i set up for the particles, so no motion blur or a good swirly-around-the-axis look. Tried couple ways but i wasn't able to do that.

Then i thought i could create a mesh from the particles, carrying on the v attrib so it would "stretch" in the way i wanted it to, and then shade it somehow. So I tried a particleFluidSurface, but no luck again. Still too blobby look and no good stretched look.

So that's the first question: any help? If i want to create that stretched tornado-cartoon-look mesh from the particles, or if i want to shade them with a fluid but having the "tornado" swirly feel?

Second question: i was trying to "convert" the particle SOPs into POPnets. Created popnet, source, damp, all good, but then i was encountering problems when using Orbit while trying to push them down with a Force. It seems that the Orbit goal always overrides the down Force. Why is that? How can i replicate the particle sop force? (Axial/Vortex forces?)

Sorry for the long post and if the questions are newbish, but i'm here to learn

Thanks.

Akabane

PS: (For the shading part, i also tried to render a i3d file, res 128 128 128), but it was rendering still after 30 mins, so i stopped. Any clue? I followed the guides from the "how to create clouds" from the houdini help)

IIRC the tornado vids were made with v5.5

That tornado was built with sprites in mind. There is a sprite shader video that covers the shading process for the tornado. The difference between the v5.5 vop shader building and doing it in h9/10 is that the shift range vop is now called the fit range vop. Sprite renders with motion blur for a tornado can get you some really nice looking effects, without the overhead calculations of using pure volumes (isooffset-way).

If your trying to get the swirly effects inside a popnet, then orbit pop is not the way to go. Use the metaball method in the vids (metaballs and forceSOPS), and add them to an attractorPOP.

[Akabane]

IIRC the tornado vids were made with v5.5

That tornado was built with sprites in mind. There is a sprite shader video that covers the shading process for the tornado. The difference between the v5.5 vop shader building and doing it in h9/10 is that the shift range vop is now called the fit range vop. Sprite renders with motion blur for a tornado can get you some really nice looking effects, without the overhead calculations of using pure volumes (isooffset-way).

If your trying to get the swirly effects inside a popnet, then orbit pop is not the way to go. Use the metaball method in the vids (metaballs and forceSOPS), and add them to an attractorPOP.

Hi, thanks for the reply.

I will look for the shading part of the tutorial in the next days, but are those sprites created procedurally or with static images?

If i wanted to create a fluid-based (instead of particle-based) tornado, do you think that i should achieve the look i'm looking for? (explained - poorly perhaps, sorry - in the op post, maybe i'll post some images of the effect later) Is motion blur with fluids good enough?

And overall, is it better to use the particle-sprite way or fluids? I mean, for a "hero" tornado, not BG ones.

Thanks again (and thanks also for the metaball-forceSOP thing in popnets, i didn't know i could use those as well )

Akabane