unwarp square faces to non square image texture

Question

I have a non square texture ( 3000 x 1000 pixels). I want to unwarp a basic cube. Since it's cube, each face is a square ( all side has same length) or let say the aspect ratio between width and height of the face is 1:1.

If select all face then unwarp (using smart uv project) , the result in the uv editor is not square. all faces are stretched.

How can i do 'smart uv project' for all the faces and get the proper aspect ratio for each faces ?

So far i can get the proper ratio by using standard 'unwarp' for each face and have to manually arrange them across the texture one by one.

Answer 1

Smart UV project can't handle non-uniform textures.
The standard UV > Unwrap works just fine, if you check ✓Correct Aspect.

^{If you insist on Smart UV Project, scale the resulting UV map to 1/3 width}