Bumpy Poly Wire?

[poppy]

Hi, first post here

I'm working on some lightning effect using curve and noise CHOP. I plugged the generated curves into polywire node for rendering. The question is how can I add "randomness" into wire thickness, you know, make it more electric-like.

I'm pretty new to Houdini, please don't geek me out .

Thanks!

Poppy

[Erik_JE]

You could use noise($TX,$TY,$TZ) as parameter for the wire radius.

[poppy]

You could use noise($TX,$TY,$TZ) as parameter for the wire radius.

Thanks, Erik_JE. one more question, how can I control the range of the noise($TX,$TY,$TZ)?

[Erik_JE]

Thanks, Erik_JE. one more question, how can I control the range of the noise($TX,$TY,$TZ)?

The noise function should return values in the range 0 to 1 if i remember correctly. Use multiply by 2 if you want it in the range 0 to 2.

[poppy]

The noise function should return values in the range 0 to 1 if i remember correctly. Use multiply by 2 if you want it in the range 0 to 2.

oic, then, if I don't want 0, it would be sth like (noise($TX,$TY,$TZ)+1)*2

[Erik_JE]

oic, then, if I don't want 0, it would be sth like (noise($TX,$TY,$TZ)+1)*2

Correct

EDIT: Over 100 posts. Celebration with coffe

Edited September 5, 2011 by Erik_JE

[anim]

actually noise should be in -1,1 range

and the easiest way to change that range is use fit() function or in -1, 1 case fit11() function

so

fit11(noise($TX,$TY,$TZ),1,2)

will give you noise remapped to 1,2 range, etc.

but basing wire thickness on point position will produce different values as the curves will move

if that is not desired you can base it on something like $PT or any attribute

you an even create custom attribute modify it in VOP SOP or CHOPS to get your thickness values per point

then simply put $variablename to Wire Radius parameter in PolyWire SOP

so if your attribute is called "width", you will put $WIDTH in there

[Erik_JE]

actually noise should be in -1,1 range

My mistake. It's the vex one that is 0 to 1

[anim]

yes, but be careful about that too since in VEX you have many types of noises and each may have different range

which is not very helpful if you want to switch between them

according to docs:

Perlin Noise (noise): 0,1

Original Perlin Noise (onoise) -1,1

Sparse Convolution noise (snoise) -1.7,1.7

Alligator noise (anoise): 0,1