I do not know if someone has tried this before.
But giving something -mass.

I was working on my own actor and I gave the head -mass and the robot balance like a dream with a floaty head.
Keeps the body up right.

For some reason when something has neg mass the jets and thursters seems to go down faster.

Awesome! But I think you need to rename this thread, there's not enough info in the title.

i've noticed that when i give things negitive mass, they do not float, but are lighter.

like when you hit them, they will be more easily thrown somewhere.

hmmm... interestingingti... hmm...

i Also found if you give Restitution X (x= any number)

It will recoil back at that speed.
Say you hit it with a nade that is going 10 miles per hour and it hits this matieral with a resitiution of 2 it will bounce back at twice the speed.

And if you give the material - resistution it will flow right through it

Hmm, i've tried negitave mass before and it didn't work like that for me. In fact, I couldn't even see a difference. Maybe i'm just not tuned in to minor changes . I'll have to work on it some more

Yes yes you will.

New intersting thing I found.

The Dropships and rockets have exit velocity.
So you can make flying cannons if you want.

But make it too fast and it lags out the game when it hits the ground and digs through it.

yep, and here is my Aerial Cannon>>

http://datarealms.com/forum/viewtopic.php?p=16060#16060

Negitive Sharpness = Implosions of Mass Destrution!!

I have not tried -sharpness.

-edit-
With -sharpness iand low mass weight you could make an actually push mod.
Yep it works. try not to hit the head though.

Also if you give round a -mass it will shoot you foward instead of backwards.

I know, I made a superman mod with that.