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# Define a plane knowing a point and the normal

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#1
Members - Reputation: **302**

Posted 11 December 2011 - 09:59 AM

Is it possible? If it's not clear I can make an image.

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#2
Members - Reputation: **952**

Posted 11 December 2011 - 11:15 AM

I'm developing an opengl application and I have cast a ray from the camera to a point in 3D space. I would like to define a plane where such point lays, with the cast ray vector perpendicular to such plane.

Is it possible? If it's not clear I can make an image.

You should be able to define this plane if you know the tangent and the binormal, which can be derived from the normal.

We know that these vectors are both perpendicular to the normal. To find the tangent you will find two vectors perpendicular to the normal and pick one depending on whether the normal is positive or negative, the binormal will be the cross product of the tangent and the normal and at that point you should have enough information to define a plane, this will however be a massive burden on your CPU if you want to do this in real time so see if you can offload some calculations to the GPU using shaders or OpenCL.

you know you program too much when you start ending sentences with semicolons;

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#3
Members - Reputation: **132**

Posted 11 December 2011 - 01:39 PM

I'm developing an opengl application and I have cast a ray from the camera to a point in 3D space. I would like to define a plane where such point lays, with the cast ray vector perpendicular to such plane.

Is it possible? If it's not clear I can make an image.

could you get the cross product between your ray and the world up vector and then the cross product of that vector with the ray

ray X worldUpVec = U

ray X U = V

plane defined by the point in 3d space, U and V.

perhaps

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#4
Members - Reputation: **1619**

Posted 12 December 2011 - 07:07 PM