1. LL is perpendicular to horizontal surface and we use the actual value from the code and design is based on the horizontal length of the beam (not the inclined length).
2. DL is perpendicular to the horizontal surface. We increase the load (DL / cosine) to compensate the sloped length. Then we use the horizontal length of the beam for the design.
3. Wind load (for the components) is perpendicular to the sloped surface of the rafter. We use the actual value and design is based on the horizontal length of the beam. The same concept as the DL.
We were questioned about this method. Is there any thing wrong with this method?