( images and animations are copyrighted: no public use is allowed without author autorization. )

Liver mesh at a given simulation time step.

Real-time rendering of the aspect (Raphael Heiss work), with the skin, the surgery marks, and reflects:

Application of the Volumetric Textures to the surgery simulation (despits the case of the liver is totally unadapted!).

( images and animations are copyrighted: no public use is allowed without author autorization. )

With my collegue Marie-Paule Cani, we published at Siggraph'99 a methode for texturing without distortion. Thanks to it, we can now texturate correctly the skin grain.

With Jean-Christophe Lombardo and Marie-Paule Cani, we published a method to detect in real-time the faces that are in contact with a tool, by using the graphics hardware of SGIs (OpenGL FEEDBACK render mode).

Pierre-Olivier Agliati has integrated the adaptive deformation simulation model of Gilles Debunne, the real-time collision detections, the reflects of Raphael Heiss, and the distortion-free textures.

With Franck Sénégas, we simulate the liver surface aspect variation in reaction to the instruments: contusions and blood drops, withening after compression, cauterisation. We use for this animated textures.
Animation of drops on a cube: (mpeg, 4.9 Mb).
Drops, cauterization, compression on a liver: (mpeg, 25 Mb).

Principle:
- make triangular texture samples whose borders are compatible. For liver skin, we use Worley procedural textures (roughly, Voronoi diagram).
- build an equilateral mesh on the surface (e.g. using Turk algorithm [Sig'92])
- project it on the surface using geodesics, and parameterize the area of triangular texture patches.
- choose random boundary conditions on the texture mesh edges, and map samples that are compatible with them.

Principle:
we introduce a system of textural sprites, obeying the 3D dynamics, but yielding simply a few texture pixels to update at each time step.

The following image illustrates at which point reflects provide an information about the relief: in the present case, neither the shading, or the shadows, or the perspective, or the depth of field give any usable 3D information. Moreover, reflects are very sensitive to small pressure changes, thus provide an extra clue about the contact and the stress.

Contact

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E-mail : Adresse : Maverick / LJK - INRIA ZIRST, 655 avenue de l'Europe
                38330 Montbonnot Saint Martin - FRANCE

Fax : +33 (0)4 76 61 54 40 Secretariat :    76 61 54 26 (NB: I strongly prefer being contacted by email)