Unity3d: Position a gameobject such that its forms a right angled triangle with other two gameobjects

Question

How do I position C gameObject such that it forms a right angled triangle with A and B. I tried to use (B.transform.position.x,A.transform.position.z) but it still gives me something which is close to A (it takes it globally). I want the C to be along the local red axis of A and local green axis of B as seen in the picture. What do I do?

Answer 1

Taking these two constraints:

• "position C gameObject such that it forms a right angled triangle with A and B"
• "I want the C to be along the local red axis of A"

We can solve this relatively easily using A's transformation:

// Transform point B into A's local space.
Vector3 bInAsSpace = a.transform.InverseTransformPoint(b.transform.position);

// Find a position along A's x-axis (y = z = 0 in A's local coordinates)
// that matches B's x-coordinate when viewed from A's frame of reference.
Vector3 cInAsSpace = new Vector3(bInAsSpace.x, 0, 0);

// Transform this position from A's local space back to world space.
Vector3 cInWordSpace = a.transform.TransformPoint(cInAsSpace);

This is guaranteed to be along A's x-axis (the red axis), since its y & z position in A's local space are both zero.

It's guaranteed to form a right-angled triangle with A & B because it forms a right triangle in A's local space (its separation from A is purely along the x-axis, and its separation from B has an x component of zero), and Unity transforms don't include shear.