[Sidefx-houdini-list] units in houdini

Garman Lists garman_lists at sbcglobal.net
Fri Feb 2 16:09:50 EST 2007

Yes, but... what about the camera.  There is a camera in there with 
focal length in mm.
As soon as you have that, then don't you have a standard?

>> Jeff Wagner wrote:
>>> I would assume that a Houdini unit is whatever you want it to be and
>>> build your tools accordingly. Steven refers to the units that are
>>> critical to DOPs when he mentions that a unit = 1 metre. Yes it is in
>>> the Preferences and was added for DOPs but that's all. A nice guideline
>>> but certainly not gospel.
>>> A houdini unit is whatever you want it to be. 
>>> Nothing is guaranteed with universal units. Units are cheated all the
>>> time. Many times in many facilities modelling many props with all kinds
>>> of different modelling tools, I have observed modellers delivering
>>> props, characters and sets in vastly different scales/units on the same
>>> job. It's a fact of life. Drives some TD's nuts. Others take it in
>>> stride and build the support needed and move on. 
>>> Tweaking scales of props, sets and other parts of a scene is an on-going
>>> issue. Units are also changed if the scene is too large or too small so
>>> you can work with it. Steven also mentioned this.
>>> You should design your effects tools in such a way that you have a
>>> single global scale parameter that properly scales the effect up and
>>> down keeping both the behaviour and any shader patterns and other
>>> scale-dependent parts properly aligned.
>>> It is doable but requires some management as you build your effects
>>> tools. If this is for general consumption, it is worth it.
>>> In shaders that use procedural patterns, you can control globally within
>>> the shader how to control the scale up and down. Helps to use "rest"
>>> attributes. Same with SOPs.
>>> Particle sims are trickier but you can with trial and error get the same
>>> behaviour as you scale the environment that the sim is in.
>>> DOPs isn't so easy. You pretty much have to scale things down then up
>>> again going in to DOPs. Then again I haven't tried to build scalable
>>> sims in DOPs yet. I would imagine that RBD sims would be easier to work
>>> around than Cloth, wires, etc.
>>> -jeff
>>> On Fri, 2007-02-02 at 06:10 -0800, steven ong wrote:

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