# question about piece movement

**URL:** <https://forum.vassalengine.org/t/question-about-piece-movement/3257>\
**Category:** Development\
**Created:** [September 9, 2010, 6:38pm UTC](https://forum.vassalengine.org/t/question-about-piece-movement/3257 "2010-09-09T18:38:16Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![fil512](https://forum.vassalengine.org/user_avatar/forum.vassalengine.org/fil512/32/2661_2.png) [@fil512](https://forum.vassalengine.org/u/fil512)\
**Post date:** [September 9, 2010, 11:01pm UTC](https://forum.vassalengine.org/t/question-about-piece-movement/3257/3 "2010-09-09T23:01:04Z")

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Tim,

Thanks for chiming in, but I don’t think this is it. The bug depends on the piece under it being invisible. If the piece under it is visible, then it stacks perfectly on top of it, but if the piece is invisible, then it is displaced by half a hex (both up and to the side). Note this is not an “expanded” stack issue. The spacing on expanded stacks is much smaller. When the unit underneath is visible, the two units are clearly stacked.

If the unit underneath starts invisible and then is made visible, the top piece will “snap” back into the centre of the square.

That’s what made me think that there must be some code somewhere that says under certain circumstances (like these two pieces can’t occupy the same hex) then if a player tries to move a piece into that hex, it will move it partway in until the conflict is resolved.

There’s no mechanic like that that you know of?

Ken  
P.S. More details are available in the bug report

> [@Tim M](#):
>
> Piece control placement is detemined by a couple of things. If a grid or region  
> has been defined a piece can snap to, furthermore in the case of grid whether or  
> not the edges vertices or centers of the grid are valid snap locations for the  
> piece.
> 
> The other factor is if the piece�uses the Does Not Stack trait with the check  
> mark option to ignore grids enabled
> 
> From your description if an edge of a grid were an enabled snap point this could  
> make a piece appear to be halfway in the hex. The only other way would be no  
> snap points or DNS w/ �ignore grid�using old fashion drag n drop of the piece  
> and a bit of luck to place the piece half way in the hex

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