If you have a group of N different objects, and N points in a point cloud, then here’s a simple way to instance a different shape at each point.
The line of shapes in the background is the group.
Note the use of Get Point ID, which works even if the points don’t have their ID attribute set.
When you’re using Get Closest Locations, positions are local. That is, they are relative to the local coordinate system of the object that “owns” the ICE tree. The input Position is in local coordinates, so in most cases, (0, 0, 0) will do fine. And if you use the output locations to get positions, those positions will be in the local coordinate system of the ICE tree owner.
https://vimeo.com/85486760
Hat tip: Gray, who has posted this several (many?) times over the years.
With Arnold, it’s all in the ICE tree. SItoA looks for attribute names like ArnoldLight_intensity and automatically uses those attributes to set the corresponding parameter values on the point_light nodes it exports to Arnold.
With mental ray, you use the Attribute shaders:
Dividing an integer N by itself doesn’t always give you 1.
I think it’s a problem in the Divide by Scalar node (the division is probably returning a scalar like 0.99999999, and then that is truncated to zero when it is converted to an integer).
A workaround is to do all your division with scalars, and then use modulo to determine whether you Round or Floor the result. Here’s an example compound by Guillaume Laforge:
A weightmap is per-point, but it’s per-point on the emitting geometry, not the point cloud. So you can’t just do a plain “get weights” if you want to use the weightmap to control particle values like Velocity or Speed.
Instead, you use get a location, like the particle emit location, and then get the weightmap value at that location. Then you’ll have a particle per-point context to work with.
When you get the weight at a location, you get an interpolated weight value.
Here’s a couple of examples of how to use a geometry query to modify certain points in a point cloud. The geometry queries return locations, and you can’t plug locations into Set Data nodes, so you need to take a different approach.
The interesting part (to me) is generating the sequence of indices. It’s too bad I have to create a second array to do it, but I keep the size down to an Nth of the original.
The short answer is that you can’t do it, not really. The best you can do is provide a URL in the compound properties
and then right-click the compound and click Open Netview on URL.
For ICE compounds, a CompoundNode property is loaded into the PPG when you inspect the compound.
This CompoundNode is like a proxy container for the actual compound, and it takes care of populating the PPG with the required controls, and finding the right help page. To do that, it just takes the name of the compound and constructs a URL like http://download.autodesk.com/global/docs/softimage2014/en_us/userguide/files/iceref_MyCompound.htm. (Hmm, having just said that, I figure if you had a local version of the help, then you could stick your own help page there, and Softimage would find it.)
For shader compounds it’s a little better, because you can put something like this in your PPG Logic, and it will work.
#ppg logic start
from win32com.client import constants
def OnInit():
Application.LogMessage( "OnInit" )
PPG.PPGLayout.SetAttribute( constants.siUIHelpFile, "http://lmgtfy.ca" )
#ppg logic end
hat tip: everybody on this thread
You don’t necessarily have to understand everything about transformation matrices to use them. Just understand then when you multiply a point by a transformation matrix, you’re applying scaling, rotation, and translation to that point all at once.
If you do want to understand more, you can use ICE to visualize what goes into a transformation matrix:
And you can do some reading 🙂
No screenshots, just videos this week.
eX-SI 