Image 3d / Metaballs / Polygons

[Div]

Hi,

I have done an image 3d tutorials ( can't remember where i find it, perhaps in the wiki )... In this tutorial we use i3d on metaballs, generated by an L-system, and that's looking pretty good... I'd like to do the same with my polygon object, but i3d doesn't seems working with other things than metaballs... Am i right? If i am, how can i "transform" my polygon object to metaballs, in order to render it with i3d ?

Thanks for your help...

[symek]

metaballs are special, because they have volume - they define field of properties - not only surface with properties. That's why i3d works so well with them. Polygons are hollow in a world of metaballs and 3 dimensional textures like i3d.

Of course depending on what you're trying to do you can use many methods to avoid this limitation of polygonal geometry... write something more!

cheers,

sy.

Edited September 24, 2007 by SYmek

[Div]

Ok, I have to make a cloud with holes looking likes numbers, Here is a capture of my poly object, which i like to render with i3d :

[edward]

In Houdini 9, it's straight forward to generate a volume primitive for rendering using the IsoOffset SOP. The key is to play around with the parameters in isooffset mode until you get a good volume representation.

EDIT: Fixed the hip file.

hello_smoke.hip

[Div]

Unfortunately i don't have houdini 9... I'll try to do your example with 8.1

[Div]

I have some errors when i try to open it with the 8.1 and with the 9.0 Apprentice Version... so it doesn't render anything... I add a IsoOffset node to my mesh, but i can't generate the i3d for this too... Is this a way to do this with my polygon object, or should i do it by hand adding many metaballs ???

[Div]

Ok, i solved my problem by creating one by one metaballs and it works great... But i still want to know if there are other ways to achieve this kind of effects with, or from, polygons.....

Thanks

[edward]

It works fine in Houdini Master (Apprentice) 9.0.717 for me here. I just use the render button. It won't work in H8.1 as I implied previously.

[Div]

I have the Apprentice version 9.0.688 and when i open your hip it prints an error :

Warning : Skipping unrecognized parameter "output". [/obj/font_object1/isooffset1]

Warning : Skipping unrecognized parameter "copyvariable". [/obj/pointlight1/copy1]

And It doesn't render anything.....

[edward]

I think you need a newer 9.0 build then. Notice that the official production build is 9.0.725

[Div]

Thanks, I'm downloading it...

[hoknamahn]

It doesn't matter which type of data you use for generation of i3d. It can be metaballs, points... whatever. But you limited to use metaballs by standard Houdini shaders. So you could write your shader which will generate i3d from for example point cloud. But maybe an easiest way for you is to emit particles from the volume of your object then stamp metaballs on those particles and then generate i3d.

[Div]

Yep, i try the particles solution, but doesn't succeed because of the detail of my object : i have smalls holes looking likes number, so copying metaballs on my particles make them disappear.... And for writing shader, i'm not yet how much experienced with Houdini...

Edited September 25, 2007 by Div