Simple Flower and Grass Field (with wind) in Houdini 16

Forums Technical Discussion Simple Flower and Grass Field (with wind) in Houdini 16

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ALMINA: Member; 154 posts; Joined: March 2016; Offline

Sept. 18, 2017 5:47 a.m.

I am trying to somehow achieve a flower field with wind in Houdini 16.

I have done until grouping the fbx file copied flowers and line copied grass with the red an black gradient color so they stay still at the bottom but I can't seem to find a good way to make it act like it's blowing in strong wind. I have tried all the noises in the attribute vop with a “add” to position. But they didn't look really good.

Then I noticed that the mountain sop has a element size option to it. Is it possible to somehow “add” the mountain sop to the position as it does in the attribute vop?

Also I am trying to make the flowers bend without distorting the actual shape.

Thanks a lot.

Attachments:
Houdini Forum Wind Question_00980.png (1.2 MB)
スクリーンショット 2017-09-18 10.47.51.png (9.5 MB)


AndyW: Member; 336 posts; Joined: Dec. 2014; Offline

Sept. 18, 2017 9:28 a.m.

Make an attribute that goes from 0-1 on the Y axis of your curves, multiply that to an anti-aliased noise in a point VOP, then add that to P. Animate the noise offset in the x or z. Group the points at the tip of the stems and copy the flowers to those points after the AA noise


ALMINA: Member; 154 posts; Joined: March 2016; Offline

Sept. 18, 2017 3:12 p.m.

Thank you very much for your reply! I am trying but I still don't know a lot. Is this the right direction?
Thanks!

Attachments:
スクリーンショット 2017-09-18 20.10.13.png (108.6 KB)
スクリーンショット 2017-09-18 20.09.54.png (155.1 KB)


AndyW: Member; 336 posts; Joined: Dec. 2014; Offline

Sept. 18, 2017 4:41 p.m.

Here's the way I would do it, really a super basic setup to start from. You can build in all kinds of controls by setting up stamp attributes, use control ramps for additional bending and layered noise etc. I hope that's helpful

Attachments:
windyfield.hip (175.4 KB)


ALMINA: Member; 154 posts; Joined: March 2016; Offline

Sept. 18, 2017 4:57 p.m.

Thank you very much! I can understand most of the parts but I have some parts that are difficult to understand.

What kind of role does the “resample” sop do in this case?

I am a real beginner in Attribute Wrangle and VEXpressions. (I try to avoid using it normally)
What is this doing in this case?

Thanks again!


AndyW: Member; 336 posts; Joined: Dec. 2014; Offline

Sept. 18, 2017 5:33 p.m.

The Houdini help docs will explain what the different SOPS do better than I can. As for VEX and Wrangles, don't avoid using them. The Point SOP is very cumbersome compared to what you can do with a few lines of VEX in an attribute wrangle, you'll never go back.

I'm making a float attribute called @normlength that is the current point number divided by the total number of points on the line, in the spreadsheet you'll see that show up as a point attribute starting at 0 at the base of the line and incrementing to 1 at the tip. That attribute is multiplying to the aa noise so there's zero displacement at the base of the line and it ramps to 100% at the top. You can use that attribute elsewhere, as an input to control the line width for instance, or a color ramp for shading


ALMINA: Member; 154 posts; Joined: March 2016; Offline

Sept. 18, 2017 7:02 p.m.

Thank you! I'll do my best to learn more!

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