Question about Unwrap UVW and Instances

[ForgeInteractive]

Hello all.

I'm relatively new to modeling and texturing. I recently purchased a book that had a great section on modeling and texturing a model for use in games. Everything seems to have worked fine but I have some questions that aren't explained in the book. (I'm using 3Ds Max 2012)

I created an object that had some pieces that were instances. When it came time to unwrap and texture, I took 1 of the instances and unwrapped it. When it came time to texture the entire model, I attached all the pieces and did another Unwrap UVW modifier. I tried the 'pack' buttons on the Edit UVW window and I was surprised to see every instance unwrapped. Not just the 1 but all 8 instances were unwrapped. Is this normal and is this how it should work?

When I didn't use the pack operations, all of the maps were layed on top of each other which seems to work just fine for mapping.

But, again, my questions are:
Should I get all 8 maps?
Is having them layered the 'correct' way to create the UVW?

Thanks in advance.

[Perversonality]

Pack takes all the individual parts and lays them out in isolation on the texture sheet. This is great if you want a different texture on each part, but if you want the same texture on all 8 then pack will bugger things up for you as you want all 8 to be exactly on top of each other (sharing the same texture coordinates)

[ForgeInteractive]

Ok, so it is normal behavior and it wasn't the result of anything I did?

That's good to know.

Is there a way to upack just one element of my model? For example, I have 4 instances of a 'leg' but 8 instances of a detail. Can I unpack all 8 details but only 1 leg?

Thanks.

[Buzzy]

Having them layered on top of each other is correct. You should be able to select only the parts you want to pack when you run the Pack tool and then manually place the legs. Or, you could potentially weld the legs all together, but then they might be tricky to pull apart later, should you need to.

Generally-speaking though, you shouldn't use the Pack tool on a game model. You should be manually packing them because the Pack tool is highly inefficient.