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splitterdevildoll · Aug 1st, 2005, 10:20 PM

Part of my program involves the user entering four 3-d (x,y,z) coordinates from a irregular surface with four corners in order to find the slope of each side; this would straighten out the sides. However, how do I find the new points from the slope? This is a translation problem.

I'd appreciate any comments/suggestions.

Thanks.

EverLearning · Aug 2nd, 2005, 12:52 PM

Quote:

how do I find the new points from the slope?

Might have to elaborate a little more...

pr0gm3r · Aug 2nd, 2005, 1:38 PM

Quote:

Originally Posted by splitterdevildoll

Part of my program involves the user entering four 3-d (x,y,z) coordinates from a irregular surface with four corners in order to find the slope of each side; this would straighten out the sides. However, how do I find the new points from the slope? This is a translation problem.

I'd appreciate any comments/suggestions.

Thanks.

slope = (y1 - y2) / (x1 - x2) -> slope on the line...

but on 3D we have to see where is the point connected to, and then find the slop of the line. (just more complex than 2D)

i.e:

line AB is located at; A(-3, 3, 0), B(3, 3, 1)

slope = (3 - 3) / (- 3 - 3) = 0/-6 is 0 ...

the Z axis is just helping to zoom in and zoom out in when the object is render.

Just find each slope for each lines. I hope thats help.

Please corrected me if I am wrong. Thanks,

splitterdevildoll · Aug 2nd, 2005, 4:38 PM

Thank you

EverLearning · Aug 2nd, 2005, 7:52 PM

Lines in 3D are described in parametric equations.
For example:
A line AB with A(1,2,3) and B(0,5,8). So the parametric equations are as follows:

x = 1 + r*(-1)
y = 2 + r*3
z = 3 + r*5

[where values for coefficient of r (or a constant) are obtained by subtracting corresponding vector coordinates, i.e. B - A, constant values (1,2,3) are initial point -- in this case coordinates of A since it is the starting point of a line, equations for BA would be different even though would define the same line in space]

or equivalently in Cartesian system:

(Toggle Plain Text)

    x - 1      y - 2      z - 3
    ------ =  -------- = --------
     -1           3          5

To see whether the point belongs to the line, all one has to do is plug in the coordinates of the point into the Cartesian (has to hold!) or find such r that makes parametric equations true [(x,y,z) would be the coordinates of the point itself]. To find a point on a line, one needs to take r to be some real number and plug it into the parametric equations.

Hope this helps.

ps: slope (or equation) of the line AB defined by A(-3, 3, 0) and B(3, 3, 1) is
x = -3 + r*6
y = 3 + r*0
z = 0 + r*1

Aug 1st, 2005, 10:20 PM	#1
splitterdevildoll Newbie Join Date: Aug 2005 Posts: 12 Rep Power: 0	Slope of an Irregular Surface Part of my program involves the user entering four 3-d (x,y,z) coordinates from a irregular surface with four corners in order to find the slope of each side; this would straighten out the sides. However, how do I find the new points from the slope? This is a translation problem. I'd appreciate any comments/suggestions. Thanks.

Aug 2nd, 2005, 7:52 PM	#5
EverLearning Hobbyist Programmer Join Date: May 2005 Location: Indiana Posts: 130 Rep Power: 4	Lines in 3D are described in parametric equations. For example: A line AB with A(1,2,3) and B(0,5,8). So the parametric equations are as follows: x = 1 + r(-1) y = 2 + r3 z = 3 + r5 [where values for coefficient of r (or a constant) are obtained by subtracting corresponding vector coordinates, i.e. B - A, constant values (1,2,3) are initial point -- in this case coordinates of A since it is the starting point of a line, equations for BA would be different even though would define the same line in space] or equivalently in Cartesian system: (Toggle Plain Text) x - 1 y - 2 z - 3 ------ = -------- = -------- -1 3 5 x - 1 y - 2 z - 3 ------ = -------- = -------- -1 3 5 To see whether the point belongs to the line, all one has to do is plug in the coordinates of the point into the Cartesian (has to hold!) or find such r that makes parametric equations true [(x,y,z) would be the coordinates of the point itself]. To find a point on a line, one needs to take r to be some real number and plug it into the parametric equations. Hope this helps. ps: slope (or equation) of the line AB defined by A(-3, 3, 0) and B(3, 3, 1) is x = -3 + r6 y = 3 + r0 z = 0 + r1 __________________ got math? yumm... "All men by nature desire to know" -Aristotle, Metaphysics Last edited by EverLearning; Aug 2nd, 2005 at 8:02 PM.

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Aug 2nd, 2005, 4:38 PM	#4
splitterdevildoll Newbie Join Date: Aug 2005 Posts: 12 Rep Power: 0	Thank you

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Programming Forums > Projects > Existing Project Development

Slope of an Irregular Surface