[SOLVED] Accessing SOP variables from python

ab30 · May 22, 2013, 6:05pm

How could one access SOP variables like these ones from python ?

 $PT - The point number. 
$NPT - The total number of points. 
$CEX, $CEY, $CEZ - The centroid of the SOP. 
$TX, $TY, $TZ - The point position. 
$BBX, $BBY, $BBZ - The relative position of the point with respect to the bounding box. These variables will always be within 0 to 1. 
$NX, $NY, $NZ - The normal of the point. 
$MAPU, $MAPV, $MAPW - The texture coordinates of the point. 
$CR, $CG, $CB - Red, green and blue color of the point. 
$CA - The alpha value for the point. 
$UPX, $UPY, $UPZ - The values of the up vector attribute for the first source. 
$UPX2, $UPY2, $UPZ2 - The values of the up vector attribute for the second source.

Particle Specific Variables

$PSCALE - The multiplier for the scale of the particles. 
$AGE - The number of seconds a particle has been alive. 
$MASS - The mass of the point. 
$DRAG - The drag coefficient for the point. 
$LIFE - Percentage of life used for a point/particle. 
$DIST - Distance of the point to an intersected surface. This attribute is created by the Ray SOP. 
$VX , $VY, $VZ - Velocity of the point. 
$ID - The particle ID associated with the point. This variable is only defined if the point is associated with a particle system that has the particle ID attribute enabled.

Edit: One can not access them directly via script, so one workaround is to use a point SOP and create a new attribute using those variables as values.

Then a SopTo CHOP can convert them into channels that one can access via python or tscript expressions.

eidolon · March 7, 2014, 10:21am

are there already any python equivalents in the meantime?

malcolm · March 7, 2014, 4:22pm

The, many of these are now accessible via Python. Start at this page to get help on it:
derivative.ca/wiki088/index. … =SOP_Class

Then dig down into attributes to learn more.

anodin · March 9, 2016, 7:32am

What is the equivalence of $NPT ?
When i use me.numPoints or len(me.points)
It’s alert me with Loop error.

I just want a simple $PT/$NPT in my Point SOP. but in Python.
Thx

elburz · March 9, 2016, 10:08pm

I would probably do something like

me.inputPoint.index / op('sop_name_here').numPoints

Does that work for your use case?

anodin · March 10, 2016, 1:42am

it could work if
op(‘sop_connect_from’).numPoints

But i thought that i could know the total number of the current sop, Local variable like in Tscript

it works in my exemple but it is not versatile
TSvsPY_COLORS.tox (1006 Bytes)

elburz · March 10, 2016, 4:45am

you can replace the op() call for me

me.numPoints

Try that?

anodin · March 10, 2016, 4:49pm

me.numPoints
and
len(me.points)

create a warning/error Cook Dependency loop detected,

Faraz.esk · August 27, 2019, 11:53am

What is equivalent of $BBY, $BBY, $BBZ in python language?
How could i access bounding boxes in python?