Transforming a scale
Blitz3D Forums/Blitz3D Programming/Transforming a scale
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| How would I transform a scale from world to local space, without using the "global" flag? Let's say I have a mesh rotated to 0,45,0. How would I make it twice as wide, in global space coordinates? Transforming the scale vector isn't the solution, as this code shows: Graphics3D 400,300,16,2 m=CreatePivot() RotateEntity m,0,45,0 TFormVector 1,1,1,0,m RuntimeError TFormedX()+", "+TFormedY()+", "+TFormedZ() Inputting a global scale of 1,1,1 would produce a local scale of 1,1,1. |
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| If you want to do it to a non-animated mesh, couldn't you simply do this: rotatemesh m,0,45,0 scalemesh m,2,1,1 (I assume you are asking how to make a mesh twice as wide in the world's x-axis after first rotating the mesh by 45 degrees about the y-axis) |
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| Since the mesh is rotated 'width' no longer means just scaling in X it also means scaling in Z too. Some adjustment to the X,Z elements of the scale matrix using sin/cos will be required but don't ask me how lol. [Edit] is it not TFormVector 0,0,1,0,m ? |
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| Okay, I want a box rotated at 0,45,0 to to fit within a bounding box that is 2x1x1. Since I want all the box's corners to touch, this requires me to change the rotation, we well. Otherwise the box would have to be skewed.  |
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| Not sure I understand you. What size is the box originally? Any box rotated 45 degress will only fit into a square bounding box e.g. 2*2*1 unless you skew it. |
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| Edit: Sorry I just realised this is not what you are after as the box inside is skewed. You mean like this: (Edit - no not like this ) Further edit: Perhaps see if you can achieve what you are after with a 3d modeling package, even milkshape, and work it out from there (not the best way I guess) Further further edit: Having a look at it on paper I agree with Shambler - without skewing it I don't think it is possible to fit a cube inside a 2x1x1 cuboid with all corners of the cube touching the sides of the cuboid Graphics3D 800,600,32,2 WireFrame True camera=CreateCamera() MoveEntity camera,0,0,-50 cube1=CreateCube() cube2=CreateCube() ScaleMesh cube1,2,1,1 RotateMesh cube2,0,45,0 FitMesh cube2,-2,-1,-1,4,2,2 Repeat angle=angle+1 x#=10*Sin(angle) z#=10*Cos(angle) y#=10*Sin(angle) PositionEntity camera,x,y,z PointEntity camera,cube2 RenderWorld UpdateWorld Flip Until KeyDown(1) |
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| It's possible, but you have to rotate it, too. I don't really want the rotations to change when objects are move, so I think scales will have to be input by hand. |
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