With ray casting engines for each column of pixels you cast a ray and collide it against world geometry to see what it hit and where. With this engine, and mos

With ray casting engines for each column of pixels you cast a ray and collide it against world geometry to see what it hit and where. With this engine, and most modern 3d engines you apply a transform to 3d world space points to get a screen space point. You also need to sort objects by distance or use a z buffer.