CODEWITHSUNDEEP
javascriptmathcanvas3dgeometry
monkeymad2
monkeymad2

Reputation: 153

Calculating 2d position of 3d point cloud data represented by angles and lengths

I'm trying to build a thing that renders point cloud data stored in a specific way to a canvas using Javascript.

The data is stored as (JSON, where -> represents a range of values including the two extremes)

{"xangle":-Math.PI*2 -> Math.PI*2,"yangle": -Math.PI*2 -> Math.PI*2,"disntancefromorigin":10,"colour":blue}

I've been having some trouble working out what the maths should be for turning the xangle, which represents the angle away from the x axis the line is and the yangle, which is the same but from the yaxis, and the distance from the origin into a "3d" point.

I've been running code which generates a large array of points the same distance from the origin with the same distance and trying to manually brute force the algorithm till i got it right - but that didn't help much.

here's an image which might make it clearer

thanks for any help, if I've not made something clear or you want to see the code just ask.

EDIT: I should add, I'm just going for an Orthographic representation (at least till I can get that working)

Upvotes: 0

Views: 386

Answers (1)

Wolfgang Kuehn
Wolfgang Kuehn

Reputation: 12926

r = distancefromorigin
y=r*cos(yAngle)
x=r*cos(xAngle)
z=+-r*sqrt( 1-cos^2(yAngle) - cos^2(xAngle) )

Edit: Last equation is from x^2 + y^2 + z^2 = r^2

You cannot say if you have to pick + or - because your problem is ill defined!

Upvotes: 1

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