Model Heart Aorta in Rhino 3D

1. Add one curve vertically between the lower branches (white).
2. Loft both branches together with this curve (red surface)
3. Trim this with a plane.
4. Loft the upper curves.
5. MatchSrf for tangency the upper to the trimmed loft.

I added a knot horizontally in the lower span of the blue surface before matching to limit the area distorted by Matchsrf.

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