Based on this tutorial I have try to make it work with triangles with no success.

this tutorial is demonstrating how to how to do picking on the a sphere, so in theory if i take the rayOrigin and rayDirection can work with a triangle.(without the MatrixTranslation for the center of the sphere), but don't because something needs to be changed regarding the rayOrigin / rayDirection.

all i want is to get the intersection point on the triangle.

struct triangle {
        D3DXVECTOR3 V0;
        D3DXVECTOR3 V1;
        D3DXVECTOR3 V2;
    };
struct Ray {
            D3DXVECTOR3 P0;
            D3DXVECTOR3 P1;
    };
...
intersect3D_RayTriangle(Ray, triangle, out intersection point);//this method works fine, if you don't put the ray data that comes from this tutorial

I use the method described in http://www.graphics.cornell.edu/pubs/1997/MT97.pdf

http://www.realtimerendering.com/intersections.html has multiple methods for ray/trianlge intersection (and is pretty much the to-go-to page for any intersection related questions)

Maybe i didn't make my self clear I already have a ray/trianlge intersection method that is working, the problem is the ray that is created by mouse clicking is some how wrong.

TestIntersection(int visibleMouseX, int visibleMouseY)
{
		float pointX, pointY;
		D3DXMATRIX projectionMatrix, viewMatrix, inverseViewMatrix, worldMatrix, translateMatrix, inverseWorldMatrix;
		D3DXVECTOR3 direction, origin, rayOrigin, rayDirection;


		// Move the mouse cursor coordinates into the -1 to +1 range.
		pointX = ((2.0f * (float)visibleMouseX) / (float)m_ResolutionWidth) - 1.0f;
		pointY = (((2.0f * (float)visibleMouseY) / (float)m_ResolutionHight) - 1.0f) * -1.0f;
		
		// Adjust the points using the projection matrix to account for the aspect ratio of the viewport.
		m_D3D->GetProjectionMatrix(projectionMatrix);
		pointX = pointX / projectionMatrix._11;
		pointY = pointY / projectionMatrix._22;

		// Get the inverse of the view matrix.
		m_Camera->GetViewMatrix(viewMatrix);
		D3DXMatrixInverse(&inverseViewMatrix, NULL, &viewMatrix);

		// Calculate the direction of the picking ray in view space.
		direction.x = (pointX * inverseViewMatrix._11) + (pointY * inverseViewMatrix._21) + inverseViewMatrix._31;
		direction.y = (pointX * inverseViewMatrix._12) + (pointY * inverseViewMatrix._22) + inverseViewMatrix._32;
		direction.z = (pointX * inverseViewMatrix._13) + (pointY * inverseViewMatrix._23) + inverseViewMatrix._33;

		// Get the origin of the picking ray which is the position of the camera.
		origin = m_Camera->GetPosition();

		// Get the world matrix and translate to the location of the sphere.
		m_D3D->GetWorldMatrix(worldMatrix);
		//D3DXMatrixTranslation(&translateMatrix, 1800.0f, 20.0f, 1900.0f);
		D3DXMatrixMultiply(&worldMatrix, &worldMatrix, &translateMatrix); 

		// Now get the inverse of the translated world matrix.
		D3DXMatrixInverse(&inverseWorldMatrix, NULL, &worldMatrix);

		// Now transform the ray origin and the ray direction from view space to world space.
		D3DXVec3TransformCoord(&rayOrigin, &origin, &inverseWorldMatrix);
		D3DXVec3TransformNormal(&rayDirection, &direction, &inverseWorldMatrix);

		// Normalize the ray direction.
		D3DXVec3Normalize(&rayDirection, &rayDirection);


		Ray r;
		r.P0 = rayOrigin;
		r.P1 = rayDirection;
		triangle tri;
		tri.V0 = D3DXVECTOR3(1.0f, 0.0f, 1.0f);
		tri.V1 = D3DXVECTOR3(100.0f, 0.0f, 100.0f);
		tri.V2 = D3DXVECTOR3(0.0f, 0.0f, 100.0f);
		D3DXVECTOR3 intersect;
		intersect3D_RayTriangle(r, tri, &intersect);

		return intersect;
}

"r.P1" sounds like a point to me, and yet you're passing in a unit vector instead.

I don't know you could expect any useful advice without telling anyone what's wrong.

"r.P1" sounds like a point to me, and yet you're passing in a unit vector instead.

I don't know you could expect any useful advice without telling anyone what's wrong.

I take rayOrigin as point 1 and rayDirection as point 2 crating a line, and i believe that is not the correct way to do it ?

ok i get it I will use the vector "rayDirection", however all the methods( triangle intersection ) I find take as input a ray that require point 1 and point 2.

r.P0 = rayOrigin;
r.P1 = rayOrigin + rayDirection;