Thursday, 24 January 2013

Melting Apple Object : Demo

Tuesday, 25 December 2012

Scattering inside of geometry

I was wondering why often is Iso Offset used for scattering.

So this post was noted for the notice.

Usually when we make up with Voronoi Fracture or something like Metaball SOP, we use Scatter SOP. In the case of using only Scatter SOP, it provides scattered points only along surface. So It would be useless for a little precise and controlled devision with Voronoi Fracture or something.




Therefore we use Iso Offset SOP when plug between a geometry and Scatter SOP.





P.S. 2013/10/26

There's another way to solve this system: to use Points from Volume.


It has a bit different way of approaching to making distance between points unlike Scatter SOP. This SOP uses Point Separation as FLIP Object DOP.





Wednesday, 19 December 2012

Transfer colour attributes of textures to points

It's just a easy way though, I actually wondered at this: How can I transfer colour attributes from textures to Points.

Yesterday I was taught a solution for it on Twitter. So I will note this.





Just prepare this network first.


Then lay down Point SOP and connect under Points form Volume SOP.
Add colour attribute to it then type expression into red channel parameter box :
tex( "$HIP/images/legoman.jpg", $BBX, $BBY, R )

and also blue, green channel:
tex( "$HIP/images/legoman.jpg", $BBX, $BBY, B )
tex( "$HIP/images/legoman.jpg", $BBX, $BBY, G )

This means tex ( filename or url, u, v, colour type )



If you decrease Point Separation in Points from Volume SOP, you will get more detailed image like this.



P.S. 2013/01/25

We can also apply image colours to points by using Point Map SOP.


Set up Image Map parameter in Point Map, then it will be done.


[References]
tex expression function : http://www.sidefx.com/docs/houdini12.1/expressions/tex
The Visible Lego Man | Badass Digest : http://badassdigest.com/2011/11/16/the-visible-lego-man/

Monday, 26 November 2012

Crease SOP

When making a model divide as keeping the edges details, usually just adding subdivision causes too smooth edges.

In Houdini, we can avoid this problem by using Crease SOP.


Just cut the SOP in queue between under a geometry flow and Subdivide SOP.


[Source]
Crease SOP

Friday, 27 July 2012

Gradation for value controls: Up-Down velocity control use

Just a few minutes ago, I've been training with Volcano tutorial from SideFX official website. And in that tutorial, I've done to control up and down wind forces(velocity). Up wind has strong power(1) and down wind affects nothing(0).

 In this way, when controlling any powers and the velocity, we use values 1 to 0. In this note, I'll note the proper way to control for this situation.



 Already, I put Box SOP, Volume SOP and Grid SOP and connected them with Volume Trail like the example below. In addition, here is the situation that I put Volume VOP SOP next the Volume SOP.

 As I wrote, there's point here, strong wind blows around up area(A value is 1. It means there's no numerical reducer) and there's no wind at the bottom(A value is 0. It means there's highest numerical reducer).

Well, in the Volume VOP SOP, as you see.


What we should focus on here is Vector to Float → Ramp Parameter → Multiply, which are connected from BBox(Bounds Box) parameter. 


 In the first place, convert container size(BBox) to 3 axis value with Vector to Float VEX. At the multiply, it calculates other value(Turbulence Noise + Wind Direction and Wind Scale) by the value before Ramp Parameter VEX. 


 A significance of using Ramp Parameter VEX is because Ramp Parameter has parameter UI like below and we're able to control how much we would get values visually and intuitionally. 






Consequently those calculations, we can get the result like below. As you can see, there's gradation up to down. This meaning is that up and down velocity has been multiplied by 1 to 0 and it's controlling as adding numerical reducing.






 [References]
PryoFX | Volcano - Houdini - 3D Animation and VFX