So, one of the exercises for my computer graphics class is as follows:

Calculate the shadow cast by triangle T onto the YZ plane P.


  • Triangle T coordinates: A=(30,10,16) B=(32,11,18) C=(31,12,24)
  • Light source L=(40,10,18)

The scene described above is as follows: there is a light source emitting light onto a triangle, the triangle is in front of a plane, due to the light there will be a shadow cast formed onto the plane.

In other exercises where we had to calculate whether or not a point was inside the shadow cast we made use of a line/plane equation. But this time it is not clear for me how calculate the points of the shadow cast.


1 Answer 1


Find the equation of each line that starts on the light and goes through a vertex of the triangle. Then make the equation equal to the equation of the plane.

Basically, lightPosition + verticePosition = lineEquation.

Then lineEquation = lineOnThePlaneEquation

Here's an example


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .