Workarounds for caching ICE attributes [and sidestepping ICE optimizations]

Posted on July 4, 2013 by xsisupport

Because of how ICE is optimized, it won’t bother setting data if you never use that data (see Beware of ICE Optimizations here). For example, suppose I have a point cloud where I set a per-point scalar value, but I never use that scalar data (because I just want to cache that value and use it later).

That scalar attribute is never used, so it is optimized away (it makes sense: you’re not using it, so why keep it?). You won’t see that attribute in the Cache Manager, and the Cache on File node won’t write it out (even if you add that attribute to the list).

One way to force ICE to evaluate the attribute so you can cache it is to create an Attribute Display property for the attribute, but disable Show Values.

Another way is to insert a Log Values node, and disable logging.

Yet another way is to use Show Values. Enable Show Values for Tagged Components Only to hide the values (if you’re going to tag components, you could set the Display % to 1).

And last but not least, if you have emTools from Mootzoid, you can use the Force Value Evaluation node, which uses a Show Values on a value that is never set.

hat tips to Stefano, Mathieu, and Vincent on the SItoA list

Screenshots of the week

Posted on July 1, 2013 by xsisupport

Constrain strand along simulated shape
by Renaud Bousquet

by Edy Susanto

Closest Location in UV space?
by Eric Thivierge

Gear PPGs with Embedded Layout & Logic

ICE Topo Symmetry Analyser

Checking what attributes are in a cache

Posted on June 27, 2013 by xsisupport

On the Read tab of the Cache Manager there’s a Dump Header button:

Dump Header dumps the cache header and attribute list to XML and pops up NetView:

If you want to dump the XML and parse it yourself, you can do it with this scripting command:

Application.DumpCacheHeader("[project path]\\Simulation\\scene_root\\pointcloud\\pointcloud_AnimTake1_[1..100].icecache", False)

Subscription Extra: CrowdFX Plotting Plugin

Posted on June 17, 2013 by xsisupport

I see there is an Extra for Softimage Subscription customers. It’s a plugin that adds two commands for exporting CrowdFX:
Export Crowd as FBX (Null Rig) – Exports a null rig for each actor including the animations created by the crowd simulation
Export Crowd as FBX (Null Rig and Geometry) – In addition to the null rig, it exports one geometry per actor enveloped to the null rig
There’s some docs on the Documentation tab in the Sub center.

Screenshots of the week

Posted on June 17, 2013 by xsisupport

particle flow control with turbulence
by Peter Agg

path through points
by Enduk

The Lorenz Attractor.Monkey style code retyping from C to Softimage ICE part 1

Understanding the “Doritos” (KineState Hack) Technique

Making Hurricane Andy

Vectors 101: Tubular Push with ICE

Vectors 101: Spherical Push with ICE

A Look Inside Gear – Parts 1 and 2

Shared ICE trees

Posted on May 9, 2013 by xsisupport

Sometimes you’ll see an ICE tree in italics in the explorer.

The italics mean that the ICE tree is not owned by the object, but by another object. By “not owned”, I mean that the ICE tree is not plugged into an execute port on an ICETree node in the stack of the object. In this case, the italicized ICETree is not owned by Growing_Strands_PointCloud, but by polymsh.

Roughly speaking, the italics mean “this ICE tree isn’t defined here, but it does use this object”.

Note that you can drag this shared ICE tree to another location in the stack.

Emitting points from polygons

Posted on May 7, 2013 by xsisupport

Here’s an ICE tree that emits points from the polygons on the emitter, using their PolygonPosition attributes.

As an exercise, I went to the trouble of using the PolygonNormal as the direction vector. That was slightly complicated, because I couldn’t use the EmitLocation attribute to get at the PolygonNormal. I had to use Get Closest Location with the new PointPosition instead. That’s because when you use positions instead of locations with Add Point (which is inside Emit from Position), then the EmitLocation attribute is “meaningless”, to quote the documentation.

There’s no such thing as PolygonLocation, so I had to use the PolygonPosition attribute.

Note also that I filtered out some polygons, so that I emitted points only from the faces of the soccer ball.

Using a texture map to filter a sample set

Posted on May 2, 2013 by xsisupport

On the emitter, get the texture map and use Color to Brightness to set an attribute. You’ll use this attribute to filter the Generate Sample Set.

On an empty point cloud, use Generate Sample Set to add points. Use the emitter attribute to filter the added points.

Creating points on a group of meshes

Posted on April 29, 2013 by xsisupport

From the docs:

Getting Scene data on Groups
When getting per-component data, such as PointPosition, the results are correct only when all objects in the group have the same number of components. As a workaround, one possible way to get, for example, all point locations is to plug the Get Data (group) node’s value into the Geometry port of a Generate Sample Set node with Emission Type set to Point and Rate Type set to All Points.

Here’s a screenshot of that workaround: