instances and polycounts

# 1 31-01-2007 , 09:35 PM

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Hi, please help me with this question:

When I duplicate an object and select instances in the duplicate menu, I expect that the number of polygons stay the same, but rather it duplicates as if they were whole other objects.
Is the instance in MAYA not what I am thinking (volumetric projections that use same polygonal data?)

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# 2 01-02-2007 , 12:17 AM

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No instances in Maya do not work that way.

An instance in Maya is a duplicate of an object that will automatically update on any changes you make to the original object.

This does mean a poly count increase as it is its own geometry in its own right, but will pickup any changes you make to the original.

Did I just repeat myself!!!:blush:

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# 3 01-02-2007 , 06:26 AM

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actually, i think they do. instances technically don't exist. if you read the help files about instances vs duplicates, i'm pretty sure it'll tell you something similar... don't know why it ups the poly count, though, since i've always thought of instances to be kinda like holograms... they sure look like they're there, but they're not.

*checks the help files hoping he didn't make that up*

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# 4 01-02-2007 , 06:46 AM

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Originally posted by NeoStrider
actually, i think they do. instances technically don't exist. if you read the help files about instances vs duplicates, i'm pretty sure it'll tell you something similar... don't know why it ups the poly count, though, since i've always thought of instances to be kinda like holograms... they sure look like they're there, but they're not.

*checks the help files hoping he didn't make that up*

Originally Posted by

Never knew that, thought it was just a mirror geo.

wonder what it does when you combine the instance to the original??

I know if your not careful with them you can end up with a huge amount of history and unused nodes that can go horribly wrong and crash your PC in an instance (no pun intended)

"No pressure, no diamonds" Thomas Carlyle

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# 5 01-02-2007 , 07:09 AM

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This is the extract from the Maya Help Files:

Copies vs. instances

The Duplicate and Duplicate Special commands let you create either a complete duplicate or a lightweight instance of the original. For example, you could create armies and forests full of duplicate objects without needing the memory or computing power to handle that much actual geometry.

An instance is like an alias or shortcut or symbolic link in a file system: it’s a visual pointer back to the original. However, each instance has its own transform node so it can have its own position, rotation, and scaling.

An instance stays linked to the original so when the original changes, the instance changes too. If you move a control point on the original, all instances automatically update. Instances do not have their own control points.

(In the Outliner an instance appears to have its own shape node but this is actually shared with the original.)

Limitations
Instanced lights have no effect.
Some functions, such as extrude and insert, cannot be used on instances.
You can’t apply clusters and deformations to instances, although you can of course use them on the original.
There is always at least one non-instanced transformation node between the instance nodes and the actual geometry nodes.
You cannot create a hierarchy of instances. If you create an instance of an instance node, Maya simply makes a new sibling.
File referencing connects objects by name. If you replace a reference with a different file, instanced objects within both files should have the same name. Otherwise you may encounter errors when retrieving the scene.

To me this means the the goe is in the scene, but Maya does not need extra computing power to calculate, so it does up ur geo counts but thats all.

Chris (formerly R@nSiD)
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