How can I add a noise to a mask? I tried using attribnoise node but it doesn't help.

you've selected attribute class: primitive by mistake on the attribnoise while the visualized attribute looks to be point class

I am still not able to get the desired result even after choosing 'primitive' in the visualize node. The noise gets applied to the entire geometry. The class was set to 'auto' in the visualized attribute node arlier. Why didn't it pickup attributes from the primitive?

Sharing a screen recording of what I experience.

You can multiply the @mask attribute by the Noise to achieve the required effect.

Just use a Point Wraggler with the following code:


Input 0 contains the mask attribute and Input 1 contains the noise attribute, like in the figure below.

Simplest way would be to deform your sphere with an attribute noise before your mask sop, then copy the mask attribute back to your undeformed sphere.

proceduralist
I am still not able to get the desired result even after choosing 'primitive' in the visualize node. The noise gets applied to the entire geometry. The class was set to 'auto' in the visualized attribute node arlier. Why didn't it pickup attributes from the primitive?

leave the visualize node on auto. The noise is being generated on primitive which isn't what you want. Change the noise to generate on points.

jsmack

proceduralist
I am still not able to get the desired result even after choosing 'primitive' in the visualize node. The noise gets applied to the entire geometry. The class was set to 'auto' in the visualized attribute node arlier. Why didn't it pickup attributes from the primitive?

leave the visualize node on auto. The noise is being generated on primitive which isn't what you want. Change the noise to generate on points.

That's what I did. Still not working. I think it's because the tutorial I'm following was made on Houdini 18.
Here's a snippet of what exactly he's doing.


I tried again. Still failing.


I have switched on all the legacy nodes in Houdini 19 using opunhide command and ensure that they load everytime Houdini starts up. Unfortunately the old attribnoise node is gone forever.

vik_lc
You can multiply the @mask attribute by the Noise to achieve the required effect.

Just use a Point Wraggler with the following code:

// multiply the mask value by the noise from 1 input and add the result to the color attribute.
v@Cd = point(1, "Cd", @ptnum) * @mask;

Input 0 contains the mask attribute and Input 1 contains the noise attribute, like in the figure below.

Image Not Found

Good old VEX code to troubleshoot everything in Houdini life. I'll try your method and get back. I try to minimize VEX in my workflow unless really necessary.

proceduralist
I have switched on all the legacy nodes in Houdini 19 using opunhide command and ensure that they load everytime Houdini starts up. Unfortunately the old attribnoise node is gone forever.

it's not gone, it's just the same name, older version
so enable Assets/Asset Definition Toolbar/Show Always
and then switch the version of your node from the top dropdown menu in Parameter Pane


here is the file with both versions of the Attribute Noise working

proceduralist
I tried again. Still failing.

It is working in your video until the type was changed away from points. The original hip file is also working after changing primitive to point. The amplitude of the noise is such that the original mask contributes much less than the noise value to the addition. The visualizer has 'treat as scalar' with length enabled, which probably not desired as this causes the values be be visualized as absolute values obscuring the actual behavior.

tamte

proceduralist
I have switched on all the legacy nodes in Houdini 19 using opunhide command and ensure that they load everytime Houdini starts up. Unfortunately the old attribnoise node is gone forever.

it's not gone, it's just the same name, older version
so enable Assets/Asset Definition Toolbar/Show Always
and then switch the version of your node from the top dropdown menu in Parameter Pane


here is the file with both versions of the Attribute Noise working

jsmack
It is working in your video until the type was changed away from points. The original hip file is also working after changing primitive to point. The amplitude of the noise is such that the original mask contributes much less than the noise value to the addition. The visualizer has 'treat as scalar' with length enabled, which probably not desired as this causes the values be be visualized as absolute values obscuring the actual behavior.

Thanks a lot @tamte and @jsmack. I compared the newer version of attribute noise with my own file with tamte's file considering the points mentioned by jsmack.



I am able to achieve the noisy mask but the whole sphere gets a shade of red in non masked areas as well. I can't figure out why is that happening.

I feel I should learn the newer node as the older one will get removed forever.

set your operation to multiply

Still the same result, (check at 51 seconds in the video). The first attribute noise is set to add, the second one has multiply. Just like you've done it in your file.

proceduralist
The first attribute noise is set to add, the second one has multiply.

ah ok, sorry, didn't check your whole video
it seems like your mask visualization range is set to Auto
and you are not clamping negative values in attribnoise postprocess, so it may be simply visualizing 0 as not black and overall may be difficult to make sense of mask values if the range is Auto

tamte

proceduralist
The first attribute noise is set to add, the second one has multiply.

ah ok, sorry, didn't check your whole video
it seems like your mask visualization range is set to Auto
and you are not clamping negative values in attribnoise postprocess, so it may be simply visualizing 0 as not black and overall may be difficult to make sense of mask values if the range is Auto

Okay. I'll check once again and get back to you. This is getting really difficult to understand. Man, thanks a lot for helping me out here. At the risk of sounding cheesy, if I ever win an award for a project that involves Houdini, in my award speech, I'm gonna thank you and jsmack besides Rohan Dalvi and Mark Fancher. You guys are so helpful. Seriously.


Edit.

Alrighty! Finally! I just checked Rohan Dalvi's video that I shared here earlier. He doesn't do any settings in his visualize node and everything comes out well for him.

Were there any changes made in Houdini 19?