Author Archives: xsisupport

Understanding how and when to use Delay Set Data

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I never really looked into Delay Set Data, so I never really understood what it did. I just assumed that it delayed setting data until something else happened. What it really does is handle situations where a multi-output port is connected to multiple Set Data ports.

Consider this ICE tree. You might think that X and Y are set to the same value (10), but that’s not what happens. You end up with X=10, and Y=15.

That’s because each Set Data forces an evaluation of the branch connected to the Set Data port. So in a tree like this, where the Add output port is plugged into two Set Data ports, you get two evaluations. First when you set X, and second time when you set Y. Consequently, X is first set to 5, and then to 10, and that all happens before the value of Y is set.

What happens with this ICE tree is like what happens in this Python snippet.

X = 5
Y = 5
X = X + Y
Y = X + Y
print X
print Y
# 10
# 10

Not like this:

X = 5
Y = 5
Y = X = X + Y
print X
print Y
# 10
# 10

To get the expected results and eliminate the extra evaluation, you could change the ICE tree so that the Add node has only one connection to the Set Data. This tree will run faster, because it has one less evaluation of the Add branch.

The Delay Set Data node addresses this issue by caching (for each Set Data port connection) the values from the first evaluation of the branch, and then setting the values all at once.

WARNING : 3000 – Objects were not saved normally

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Occasionally I’ll see reports of this kind of error. Sometimes I see it when I’m investigating some other problem in a scene.

// WARNING : 3000 - Save: [1] objects were not saved normally
// WARNING : 3000 - -- [Framebuffer<1004>] was saved, but is disconnected from the scene. (Floating object)

You can use Dictionary.GetObject to get the floating object and interrogate it:

var x = Dictionary.GetObject( "Framebuffer<1004>" );
LogMessage( ClassName(x) );
LogMessage( x.Parent );
// INFO : C:\Program Files\Autodesk\Softimage 2012.SAP\Application\bin\XSI.exe
LogMessage( x.Parent3DObject == null );
// INFO : True
LogMessage( x.Owners.Count );
// INFO : 0
LogMessage( x.RenderChannel );
// INFO : Normal
//LogMessage( x.GetResolvedPath(0) );
// ERROR : 21000 - Unspecified failure - [line 15]

And you could even delete the floating object before you save the scene:

DeleteObj( Dictionary.GetObject( "Framebuffer<1004>" ) );

However, there is a scene debugging preference that allows you to “skip the loading of floating objects”. This preference was added back in 2004 or so to deal with “ghost models” (which are basically floating or disconnected objects).

You could also try printver -cleanfloating to remove floating objects. I don’t know if that still works, I haven’t used it three or four years.

Another thing you can try is to merge your scene into a new scene. The warning could be a “false positive”. If the warning is gone after the merge, then it was indeed a false positive (which means that something, such as the schematic view, was still holding on to a reference to a deleted object).

The case of the While loop that didn’t evaluate

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In this case, an ICE While loop wasn’t working as expected.
The customer was using Max Repeat to do something like this, but in ICE:

x = 2
cond = x > 0

i = 0
while cond:
	print i
	i = i + 1
	if i > 10: break

Unfortunately, in ICE, the While loop was never executed.

It’s not a problem with the While loop, it’s a problem with the ICE tree evaluation (it’s a bit too lazy). I’ve seen things like this before, and I usually create a separate ICE tree to workaround it:
http://vimeo.com/33968117

On the mailing list, Guillaume suggested a couple of other workarounds. First, use Delay Set Data.
The word “Delay” in the node name throws me off…I wouldn’t think to use it, but after reading up on it, I can see why you would think to use that node (it does evaluation).

If you set the condition boolean in the While loop, that works too:

Top 10 things to learn for the ICE newbie

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Last week there was a Top 5 things to learn about ICE? thread on the mailing list:

If you ICE experts out there had to recommend the top 5 (first) things to learn about ICE what would they be? I’m looking for cornerstone/pedestal type foundation items. I’m going to put some time into really learning ICE and I’d like to know what the most valuable concepts are.

There were several good responses, so I’ve combined them all and added a few more to make it a “top 10” (rather than a top 7). Also, I added some links to relevant videos (mostly my own). I’d also recommend you watch Paul Smith’s tutorials, starting with 1. What does ICE do?.

Also, see these video tutorials:

Placing instances on polygons

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Over on Vimeo, commenter LBX (check out his multiple texture map vids) suggested an alternative approach to placing objects on the polygons of a sphere. (See my ICE modeling posts here and here.)

Here’s the ICE tree (which is on a point cloud of course 😉 The use of PolygonNormals and the sphere radius is neat.

To deal with more general geometry, I think you’d need to do something like this:

Friday Flashback #48

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Three years ago, 15 Dec 2008 was my first day in the Autodesk offices. Officially, I’d been an Autodesk employee since sometime in November, but 15 Dec was the first day I reported to work at Autodesk.

I’m cool working at Autodesk and I still enjoy what I do, but I kinda miss our old offices, in the old Reitmans factory building on St Laurent boulevard. After the acquisition, the Max/Maya support guys came up to visit and do lunch, and their jaws literally dropped when they saw the offices where me, Manny, and the other support guys sat.

On the other hand, the Autodesk offices are perfectly located for a cyclist like me. To get to Softimage I had to actually bike into the city, whereas the Autodesk is down at the Old Port, practically right at the end of the bike path along the Lachine canal.

Here’s some pics of the old Softimage headquarters:

This slideshow requires JavaScript.

I’ve pulled out the panorama of Erik’s office so you can get a better look at it. Erik was a “cool dude” on the Softimage support team, and his office was the most fun. He had one Hot Wheels toy car pinned to wall for each month he worked at Softimage.

ICE Modeling – placing copies on another object

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Part 1 of 2. A video walkthrough of how to use ICE modeling to create copies of an object and place them at specific positions on another object (in this case, on the polygon centers).
http://vimeo.com/33667035
Uses: Create Copies from Polygon Mesh, Transform per Copy, Get Copy Index, Build Array from Set, NbPolygons, PolygonPositions