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What command can define a point free in xOy which can not move on z-axis ?
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What command can define a point free in xOy which can not move on z-axis ?
You can use A=PointIn[x>=0&&y>=0]
For new points you can click with the point tool on the x-axis or define it with the command Point[xAxis]
But if the point is already there then you need to go to the definition in the property view and change the defintion to Point[xAxis]. Or just redefine it.
Thanks, but I know that. I am interested only in xOy plane and NOT on z-axis. Without an duplicate plane of xoy.
I don' t what you want ... pleade explain it more exactly.
hi
when you create a plane a as z=0 and the a point A=Point[a], you've got a free point in the xOy-plane which you cannot move vertically.
Point[xAxis] move only on x-azis. Not on xOy plane .
I created a plane identical with plane xOy (a) and I positioned to him my point (PointIn [a]).
I think there is a command to put point directly on xOy plane ...
Please tell me what do you not understand
hi
A=Point[z=0] will do directly without creating a plane first.
chris
Ah ... I did not understand it correctly what you mean.
This point can have positive coordinates ?
ex: Point A = [z = 0, x> 0, y> 0]
this sintax is not possible.
you can do an "on update" script similar to this post
https://www.geogebra.org/he...
hi
but you can create something that looks like it. When you create veelhoek1=Polygon[(0,0), (50,0), (50,50),(0,50)] then PointIn[veelhoek1] will have positive x and y and z=0. (If you want to avoid 0, you can use (50,0.1) ore something like that).
Sometimes we have to content ourselfs with the result of a trick instead of simple beauty...
chris
This is the simplest solution. Thank you ccambre and mathmagic for good answers
I found a syntax out of help. I hope it is not a bug.
I tried dynamics coords in 3D for B=(x,y,z) 0<x ; 0<y ; 0<z
this is the work
move B in three directions
it is easy another conditions for B
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