How do I build this structure? Method to the randomness.

[iceneko]

Hi everyone, I'm new to the Houdini game but have been working in the industry for a while. I'm currently making the long overdue transition onto Houdini from Softimage, so please bare with me  I have a question that I'm hoping some of you can help me out with. My aim is to build the structure that I have attached to this post. My initial thoughts are:

- To build the rough shape as a repeatable pattern (completed this so far and attached it!),

- from this surface/volume I emit a bunch of points and link them up with a corresponding point to make a line.

- Do some fancy noise/turbulence and yet still keep the overall volume / shape / flow . 

It's this last stage I'm having the most trouble with, I can't get a decent noise that still maintains the volume. I'm also unable to really flow the points around/within the curvature of the mesh in a way that matches the reference. I'm still really new to Houdini so I'm sure I'm missing some obvious tricks. Does anyone have any ideas?

It's worth pointing out that I've been looking at the methods of generating lines via volume trails and at least from what I can see, the curl-noise doesn't seem to do it? It's a nice effect but not the right look. I imagine it would be something more a long these lines but I still need to figure out the shapematching / flow aspect of it.

https://vimeo.com/190948059

Regards,

Tim

BuildStrandVolume.hipnc

Edited March 6, 2017 by iceneko
spelling

[Sean Lewkiw]

Have you seen this awesome tutorial?  http://www.entagma.com/houdini-curl-noise-flow/

[trzanko]

Are you starting with a grid to get the bumpy form? If you are you could set it to rows, so you have line primitives with many points, process it to give it bumps and then for each row create as many duplicate threads as you want. Add noise to each of these threads an offset it slightly from the parent thread, this would essentially be a hair up-res. Let me know if this makes sense, hope this helps.

-Tighe

[iceneko]

Thank you Lewkiw and Trzanko, I've had a look at the Entagama tutorial and I'm loving the effect. My only worry with it is it creates a lot of similarity in the shapes  and it's very flow-ey, so I'm not sure it would be the right type of noise. I might try with a different type of noise and frequency and maybe that would work better. 
 

I like the method your describing Trzanko, and I think it would be a good start in order to fill up the volume, however I still need to find a way to get the noise conform to the shape a bit more. It's like in the construction of the material they took a nice puffy cloud of fibers and pressed them together to fit a precise mould. You really get a sense of the fibers wrapping around the holes and conforming to the surface. I actually did some tests where I use a ray node to try and stick back on the shape, but I was getting some artifacts where the linewould jump from one hit to another, maybe I need to look back into this. I also adding points within each hole, maybe there's some kind of vector math I can do with this.

Just reading over this post I think I need to combine both methods from above, would there be a way to create the rough mass of fibers and then use some kind of curl noise / vel technique to help reform the lines to the surface?

 

[samvac]

Hi there, 

this method could work

BuildStrandVolume2.hipnc

[samvac]

Heres another version with base width,

hit render and have a play round with base width and point count / jitter

BuildStrandVolume3.hipnc

[trzanko]

On 3/7/2017 at 4:46 AM, iceneko said:

Thank you Lewkiw and Trzanko, I've had a look at the Entagama tutorial and I'm loving the effect. My only worry with it is it creates a lot of similarity in the shapes  and it's very flow-ey, so I'm not sure it would be the right type of noise. I might try with a different type of noise and frequency and maybe that would work better. 
 

I like the method your describing Trzanko, and I think it would be a good start in order to fill up the volume, however I still need to find a way to get the noise conform to the shape a bit more. It's like in the construction of the material they took a nice puffy cloud of fibers and pressed them together to fit a precise mould. You really get a sense of the fibers wrapping around the holes and conforming to the surface. I actually did some tests where I use a ray node to try and stick back on the shape, but I was getting some artifacts where the linewould jump from one hit to another, maybe I need to look back into this. I also adding points within each hole, maybe there's some kind of vector math I can do with this.

Just reading over this post I think I need to combine both methods from above, would there be a way to create the rough mass of fibers and then use some kind of curl noise / vel technique to help reform the lines to the surface?

 

As I started reading the second paragraph in your response I too came to the conclusion of using a ray to get the lines to conform to the shape - haha. I don't ever use the ray sop, I use the intersect function in vex in a wrangle to project points when I need to, this way I can set the ray direction better and have finer control. Also using a higher resolution mesh to project to would give you a smoother result. 

A more intricate way of doing the ray that would account for a line that's already been projected above it(overlap). The method would be to iterate over each strand and project it to the geo, looking to see if there is another point within a cone of the points normal and an angle. Then you would only be able to ray by the distance of the two points multiplied by a parameter say .9. 

Hope this helps!

-Tighe

[iceneko]

Cheers guys, I'm taking a look now and thank you for the help. I think I'm getting somewhere, I'll try and get some stills out when the job is finished.

 

Tim