Realistic Rendering of Plant Leaves

This paper discusses a geometric and optical model for realistic realistic of plant leaves. We have used a model for deformable thin shells to represent the naturally curved shape of leaves and its dynamic reponse to impulse, shear and stress. The optical model uses a simple BRDF function, combined with a transparency map for each leaf. We show that we are able to generate realistic images, without having to model complex spatially varying BRDF functions on the leaf surfaces. 1 Modeling Leaves as a Thin Shell Leaves, unlike other deformable objects like cloth, rubber, have an undeformed curved shape. There has been lots of research into modeling deformable objects in the recent past, where materials like cloth have been modeled as a layout of triangulated tiles, where the dihedral angles at the edges between the tiles change. There are mainly two kinds of deformations: 1. Intrinsic: Shear, Stress. Membrane deformations: Modeled using a springmass system. Preserves areas and lengths over the triangulated surface. 2. Extrinsic: Beam bending (isometric). Modeled using torsional energies (and torques) on edges. Preserves shape of the model.