new to rigging and mesh- please help!

[Lolobean]

ok so after month of trying to figure out blender, i have it for the most part. i downloaded marvelous designer, and made a few strapless things, those came out... ok. still working on it. ive watched a crap ton of tutorials on rigging and making fitted mesh. so here is my question:

i made a shirt with short sleeves,( i am using the skeleton and avatar provided with it for fitted mesh) it fits on the avatar in blender just fine..

when rigging the shirt i select the shirt, then the skeleton and ctrl P and set it to automatic, then select the body and the shirt  and go to weight paints and transfer weights. i test it in blender and bend the arms around in pose mode, everything is ok with very VERY little tearing when contorted into strange positions.

when i upload the shirt into blender, i set it as a .dae and set it for secondlife- here is where the issue comes in:

when i put the shirt onto a standard size the sleeves cut into the body - even when standing still without any movement. the body pokes through in some spots when moving which i kindof expected, but i feel like none of it should be poking through with the way it fits in blender when i move it around.. 

am i doing something wrong here?  I've tried to adjust the body in any way possible and it still doesnt fit right in the sleeve area no matter what i do, and alphas are a whole nother ball game - they never fit right even when painting them on in blender and fixing them in photoshop etc. 

what am i doing wrong?

[Lolobean]

http://gyazo.com/db5cd8dea2fd80ea197e41e75a74478d

http://gyazo.com/c6055629eb448e9fbf23634febc224e1

this is what i see if that helps any... im starting to think it's on uploading it and there are too many triangles or something.... im assuming that when on upload, under physics, it should be on higher rather than on lower

 

[Lolobean]

Update:

so i tried changing the triangles in md into rectangles and there is a major improvement but back to the other question of mine: what is the difference in upload on the level of physics? if it's of higher quality, will it not allow my body to poke through so much?

thanks to anyone who can answer my question

[Gaia Clary]

Forr rigged mesh the physics is irrelevant (as far as i know) so you can just use a simple triangle as physics mesh if you like. the physics mesh does not have influence on the mesh shape.

[Lolobean]

oh wow.. ok so uploading it at the lowest physics level is ok? and what about level of detail? does that make a difference? i would also assume that level of detail would have some pull in how the mesh looks- i believe it's how it looks from far away?