Dot Product and VOP Noises

Forums Houdini Indie and Apprentice Dot Product and VOP Noises

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luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年1月5日 13:54

Does anyone use angle controls to displace noises in an attribute VOP?

For example, I want to displace on a surface area of 65° relative to the Y axis.

More example, take a tessellated cube and rotate from its natural default position. As the faces angle, the set noise on the certain degree begins to reveal.

i'e been told Dot Product does this but i need some hand holding examples.

this image shows my goal. smooth noise to heavy noise at a different angle

Edited by luidox - 2020年1月5日 22:01:00

Attachments:
82061104_2439528126286215_3389560994270281728_n.jpg (88.4 KB)


Konstantin Magnus: Member; 670 posts; Joined: 9月 2013; Offline

2020年1月6日 12:16

You would compare a vector pointing upwards against the surface normals using a dot product.

Attachments:
dot_displace.hipnc (87.6 KB)

https://procegen.konstantinmagnus.de/ [procegen.konstantinmagnus.de]


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年1月6日 13:33

thats really nice. any chance of seeing this in a vop solution? im not really a fan of vex. im an old school artist and as such we artist don't think that way

also i guess im kinda looking for something with more of a numerical literal control. like

turbnoise shows at angles 0-30 degrees
unifiedstatic shows at angles 31-60
worley shows at angles 61-90

so on

Edited by luidox - 2020年1月6日 13:44:54


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年1月7日 13:07

bump


mestela: Member; 1737 posts; Joined: 5月 2006; Offline

2020年1月8日 0:44

Like this?

Attachments:
noise_dot_blend_vops.hipnc (206.9 KB)
Selection_088.png (123.1 KB)

http://www.tokeru.com/cgwiki [www.tokeru.com]
https://www.patreon.com/mattestela [www.patreon.com]


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年1月9日 18:03

mestela im trying to utilize angle only with the ability to do this with an infinite amount of noise. that way im not confined by typical vector direction but angle.

Edited by luidox - 2020年1月9日 18:08:09


mestela: Member; 1737 posts; Joined: 5月 2006; Offline

2020年1月9日 19:50

You can convert that 1 -> 0 -> -1 value that a dot product returns into a 0 90 180 degree value if you're so inclined.

http://www.tokeru.com/cgwiki [www.tokeru.com]
https://www.patreon.com/mattestela [www.patreon.com]


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年1月13日 16:58

mestela
You can convert that 1 -> 0 -> -1 value that a dot product returns into a 0 90 180 degree value if you're so inclined.

im not too sure which value your saying should be changed. in the dot product i tried messing with the numbers and got less than desirable results.

im also not sure how to add more noises. say maybe something like 50. i would never need that much but it would be nice to have the freedom

Edited by luidox - 2020年1月13日 16:59:30


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年3月14日 17:53

could this be done in a volume vop? i tried copy past and rehook but nothin worked

Edited by luidox - 2020年3月15日 03:59:39


Nicolas Longchamps: Member; 37 posts; Joined: 8月 2015; Offline

2020年3月16日 21:35

Yes, by using the SDF gradients.
Given an SDF, you can do a dot of a vector (up in your case, 0,1,0) with the gradient of the distance field.

Attachments:
VolDisplacePiggy.hiplc (290.9 KB)


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年3月21日 17:05

i took the above and tinkered around.

you can see my botched attempt here. im trying to use dot products with trig math to assign angles to each noise. ideally instead of having it project like a 6 planer set up id like it to work based on numerical angle inputs. im shooting blanks here and in need of some guidance please

the gradient l like above is fine too

Edited by luidox - 2020年3月21日 17:39:44

Attachments:
Volume_Dot_Product2.hipnc (390.1 KB)


blackpixel: Member; 182 posts; Joined: 4月 2009; Offline

2020年3月28日 8:50

If you want numerical control as a mask, then just feed the angle with some offsets into 2 Fit Range VOPs and multiply them. Wrap the whole thing into an HDA and you should be good. You can also modify it to use another angle instead of thickness if you need something like 30°- 60°.

The example by Konstantin Magnus gives you much nicer ramp controls though and I'd argue that you could recreate that snow image with mestela's solution:

Edited by blackpixel - 2020年3月28日 09:05:04

Attachments:
fit_mask2.gif (3.7 MB)
capture_snow.JPG (85.6 KB)
fit_mask.hiplc (163.9 KB)


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年5月31日 14:17

blackpixel
If you want numerical control as a mask, then just feed the angle with some offsets into 2 Fit Range VOPs and multiply them. Wrap the whole thing into an HDA and you should be good. You can also modify it to use another angle instead of thickness if you need something like 30°- 60°.
Image Not Found

The example by Konstantin Magnus gives you much nicer ramp controls though and I'd argue that you could recreate that snow image with mestela's solution:
Image Not Found

This has worked great. is there a way to get import point nodes to work with this?? i am not having much luck and getting alot of exploded verts as a result.

Edited by luidox - 2020年5月31日 14:18:25


Aizatulin: Member; 472 posts; Joined: 7月 2005; Offline

2020年5月31日 16:32

If you want a variable number of different noises, you can use a multiparm list. Here is a vex approach, but quite similar to the

previous examples.

Edited by Aizatulin - 2020年5月31日 16:33:08

Attachments:
noise_by_angle.hipnc (94.1 KB)


luidox: Member; 36 posts; Joined: 10月 2018; Offline

2020年6月19日 18:11

Aizatulin
If you want a variable number of different noises, you can use a multiparm list. Here is a vex approach, but quite similar to the

previous examples.

is there a way too have this sphere example work based on position rather than angle? im trying to position noise info on a set of stairs but i don't want to noise to touch every stair case. id like it to work its way up functionally rather than work on all similar angles.


Aizatulin: Member; 472 posts; Joined: 7月 2005; Offline

2020年6月20日 7:59

Instead of the angle you can use a float point attribute, which gives you more freedom. You can use the height, the angle, captured

attributes from another geometry or whatever you want. In my example the name of the attribute is “u”.

Attachments:
noise_by_attribute.hipnc (102.4 KB)

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