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Bakingsoda36

World Space...

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Bakingsoda36    211
I’ve been trying to figure this out for a while now but cant find anything good on it, and I searched on google and stuff but couldn’t find anything so I was just wondering what is the difference between Screen Space, Model Space, and world Space in Direct3d? Thnx

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SnakeHunta    148
world space - starts at origin (0.0f, 0.0f, 0.0f) at center of screen and goes out on the x,y,z axis
screen space - starts at x,y (0,0) at upper left corner of screen and gets large to the bottom right corner of screen
model space - do not know

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Bakingsoda36    211
Do u use all three or just one? And Does it matter which one I use? (sorry for such a newbie question)

[edited by - Bakingsoda36 on March 17, 2003 10:38:38 PM]

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falkone    444
The use of global and local coordinates are meant to simplify. It is also required for accurate scaling and rotation. (if you want to rotate a model around it's z axis, then using the global z axis will not work.. same with scaling). It makes it much much simpler and is required in many situations

EDIT: I assume by model space they mean the coordinate setup that is local to the model. The 0,0,0 is usually at the center of the model.. the center of rotation and scaling

[edited by - falkone on March 17, 2003 10:46:25 PM]

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alnite    3438
??? (puzzled with so SnakeHunta definition) ???

I thought World Space is a space representing the..world. It's where the objects are placed. So, if we have books, a pencil, and a piece of paper as our objects, the world space will be where these objects are located, such as a table.

Then, View Space is how the table is represented from a "camera" (i.e, your eye). And the screen space is how the view space is represented on the screen. No?



Red = the origin of view space
Blue = the origin of world space
Green = the origins of model spaces

EDIT: Added the illustration.
EDIT: Illustration fixed. The table was missing due to the black background


throw Exception( "End of post" );

[edited by - alnite on March 17, 2003 11:23:05 PM]

[edited by - alnite on March 17, 2003 11:36:48 PM]

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falkone    444
Yes..

An example of world coordinates would be.. lets say a pencil.. we''ll say that the world origin would be the center of the table this player is resting on (it''s all relative, one set of global coordinates can be another''s local)... it could be 2,2 units from the center. Now, the 2,2 only describes the pencil''s location. It could just as easily describe the location of a bus.. it does not define the shape of the object. The coordinate system local to the pencil will then have it''s origin set at global 2,2. From here we can describe the point at 2,3.. and the eraser at 2,1.. and all the vertices that may make up the pencil..

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alnite    3438
quote:
Original post by Bakingsoda36
Do u use all three or just one? And Does it matter which one I use? (sorry for such a newbie question)
You use all. They are all part of the geometry pipeline.




throw Exception( "End of post" );

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