Forums > Jitter

### learning jitter expressions

Feb 24 2010 | 9:18 am

I try to learn jitter expressions because there the core of jitter . Can you recommend good books (maths or other anything) that can help me to understand these "mysterious" expressions.

Feb 24 2010 | 11:35 am

the easiest way is to create a new object and start typing either "cv.jit.___" or "jit.___" and select any of the object expressions that appear in the drop-list. then (in edit mode) alt+click the object and learn more about, copy it, edit it-whatever you please.

Feb 24 2010 | 12:05 pm

Feb 24 2010 | 2:02 pm

i have no idea. :(

Feb 24 2010 | 6:11 pm

there’s plenty of examples on the forum, as well as in the jitter recipes.

other that that, i would say, stay tuned to the cycling74 articles website.

Feb 24 2010 | 6:41 pm

Thanks , I know there plenty of articles but the problem is that i don’t have a knowledge base and when i want to put my ideas in practice i realize that i’m lost.

The forum is like a candy store. A lot of tastes hide the ingredients :)

Feb 25 2010 | 11:20 am

I speak about expressions like :

expr " pow(min(norm[0] , sqrt(norm[1])) , 2.0)"

or

expr sin(norm[0]*(2*PI))*sin(norm[1]*(2*PI))

or

I was not very good of math ( I know basic geometry) so i tried to find some good books. I need to study analytic geometry or matrices? Can you recommend some books that will illuminate me ?

Thanks

gobo

Feb 25 2010 | 6:01 pm

i can’t really think of a much better resource than the googles.

this guy’s site is chock full of information and equations:
http://local.wasp.uwa.edu.au/~pbourke/geometry/

most of these geometric shapes can be created with jit.expr and jit.gl.mesh.

for a more concrete example, recently i wanted to create a spiral shape, so i googled spiral equations, or something like that, and found this:
http://www.mathematische-basteleien.de/spiral.htm
on down the page if found the spiral equation in needed
x=tcos(6t) y=tsin(6t) z=t

i plugged this into jit.expr using norm[0]*5 in place of t (found by experimenting), and plugged the output into jit.gl.mesh. viola.
‘jit.expr @expr (norm[0]*5)*cos(6*(norm[0]*5)) (norm[0]*5)*sin(6*(norm[0]*5)) (norm[0]*5)’

hopefully this is helpful, but if not, as mentioned, stay tuned.

Feb 26 2010 | 11:57 am

Thanks , I will try to learn using trial and error. if I will be blocked , I will ask on forum.

Feb 26 2010 | 4:05 pm

@robtherich can you expand on how this works in patch form. i just tried to code this as u describe and i get nothing…

could you post your spiral patch so we can get an idea of how u implemented this.

thanks

j

Feb 26 2010 | 6:39 pm
``````
-- Pasted Max  Patch, click to expand. --

```
```
Feb 26 2010 | 7:48 pm

thanks v much for the share.

j

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Forums > Jitter