Implicit Models & Meshes

Presentation

We propose to study and develop simple to implement, intuitive and robust tools for modeling tridimensional objects in order to generalize to most people the access to the development and the use of modeling and animation software. A substantial impact on the general public is the access to both the expression via the creation and the animation of tridimensional virtual objects, and the free creation of real objects using, for instance, 3D printers. To reach our goal, we propose to lean on the natural properties of implicit surface representations and to tackle the scientific challenges that prevent their wider practical use. We also wish to demonstrate the strength of implicit representations when they are used in conjunction with standard mesh representations in applications such as deformations (skinning, visually plausible crushing) and collision detections.

Ce projet propose la définition et le développement d'outils simples et robustes pour la modélisation d'objets tridimensionnels. L'objectif à travers ces outils est de permettre une démocratisation des logiciels de modélisation et d'animation d'une part en simplifiant leur développement mais surtout en proposant une grande accessibilité et une utilisation simple pour la prise en main rapide de ces outils par tout public. L'impact au niveau du grand public est important aussi bien pour permettre l'expression via les objets tridimensionnels statiques et dynamiques que pour faciliter l'accés à des outils de fabrication comme les imprimantes 3D. Pour ce faire, nous proposons de nous appuyer sur les bonnes propriétés naturelles des représentations d'objets tridimensionnels par surfaces implicites et de résoudre les verrous scientifiques qui bloquent leur plus grande utilisation. Nous souhaitons aussi démontrer la puissance de cette représentation quand elle est utilisée en conjonction avec des représentations classiques par maillages dans des applications de "skinning" et de gestion des collisions avec des déformations comme l'écrasement.

	2010 O. Gourmel, A. Pajot, M. Paulin, L. Barthe and P. Poulin. "Fitted BVH for Fast Raytracing of Metaballs", Computer Graphics Forum, 29(2), proc. of EUROGRAPHICS, pages 281-288, 2010. [pdf] [video] [more] [vimeo]
	2010 A. Bernhardt, L. Barthe, M-P. Cani and B. Wyvill. "Implicit Blending Revisited", Computer Graphics Forum, 29(2), proc. of EUROGRAPHICS, pages 367-376, 2010. [pdf] [video] [more] [vimeo]

Consortium

Partners involved in the project

Results

Topology-Aware Fluid Simulation: on Advanced n-Ary Composition Operators

This video illustrates the use of complex and massive function compositions with controlled and dissymmetric blending behaviors. We apply these graph-based new operators on point-based fluid simulations. We thus introduce a way for accurately controlling the fluid simulation and behavior at interfaces. Published at Symposium on Computer Animation 2016.

Elastic Implicit Skinning

This video illustrates the use of field function compositions for improving the realism of skin deformations at joints when animating an articulated model. A tangential relaxation scheme derived from the ARAP energy controls mesh distortions. This technique is interactive and improves field function based mesh deformations. Published at Siggraph Asia 2014 (Transactions on Graphics 33(6)).

Implicit Decals

This video illustrates the use of n-ary composition operators (here, contact and overlapping operators) for the interactive creation and editing of textures composed of repetitive patterns. This work is not directly in the IM&M project. It is however closely related as it is a first experience with controllable n-ary operators. This research has been published in Computer Graphics Forum 33(1), 2014.

Implicit Skinning

This video illustrates the use of field function compositions for improving the realism of skin deformations at joints when animating an articulated model with geometric skinning. This technique performs in real-time and introduces the concept of field function based mesh deformations, especially in the presence of contact. This research has been published at Siggraph 2013 (Transactions on Graphics 32(4)).

Gradient-Based Blending

This video illustrates how the composition of implicit surfaces using union, intersection, difference, blending and bulge-in-contact can be done in an effective manner by avoiding standard artefacts (blend at distance, unwanted bulge, etc). This theoretical research work has been published in Transactions on Graphics 2013 (32(2)).

Animated VORTEX's Logo

Using the results presented in "A Gradient-Based Implicit Blend" by Gourmel et al (partially funded by IM&M), only five equations and a simple ray-tracer are required to produce this video. We use three field functions of R3 in R for representing the ground, the logos sheres and removed extruded object. We also use two operators of R2 in R: one clean union/difference operator for the construction of the logo and one bulge-in-contact operator to handle its deformation when it comes in contact with the ground. All contact deformations are thus automatically generated. In this animation, no collision test and no mesh is used.

Publications

Journals

	2015 E. Entem, L. Barthe, M.P. Cani, F. Cordier and M. van de Panne. "Modeling 3D Animals from a Side-View Sketch", Computer & Graphics, 46, proc. of SMI'2014, pages 221-230, 2015. [pdf]
	2014 R. Vaillant, G. Guennebaud, L. Barthe, M.P. Cani and B. Wyvill. "Robust Iso-Surface Tracking for Interactive Character Skinning", ACM Transactions on Graphics, 33(6), proc. of ACM SIGGRAPH ASIA, 2014. [pdf] [video] [vimeo] [YouTube] [transfer] [more]
	2014 E. de Groot, B. Wyvill, L. Barthe, A. Nasri and P. Lalonde. "Implicit Decals: Interactive Editing of Repetitive Patterns on Surfaces", Computer Graphics Forum, 33(1), pages 141-151, 2014. [pdf] [video] [vimeo]
	2013 F. Canezin, G. Guennebaud and L. Barthe. "Adequate Inner Bound for Geometric Modeling with Compact Field Functions", Computer & Graphics, 37(6), proc. of SMI, pages 565-573, 2013. [pdf]
	2013 R. Vaillant, L. Barthe, G. Guennebaud, M.P. Cani, D. Rhomer, B. Wyvill, O. Gourmel and M. Paulin. "Implicit Skinning: Real-Time Skin Deformation with Contact Modeling", ACM Transactions on Graphics, 32(4), proc. of ACM SIGGRAPH, 2013. [pdf] [video] [vimeo] [YouTube] [transfer] [free codes] [more]
	2013 O.Gourmel, L. Barthe, M.P. Cani, B. Wyvill, A. Bernhardt, M. Paulin and H. Grasberger. "A Gradient-Based Implicit Blend", ACM Transactions on Graphics, 32(2), presented at SIGGRAPH in July 2013. [pdf] [video] [vimeo] [Downloads]

Conferences

2016 F. Canezin, G. Guennebaud and L. Barthe. "Topology-Aware Neighborhoods for Point-Based Simulation and Reconstruction", Eurographics/ACM Siggraph Symposium on Computer Animation, July 2016. [pdf] [video] [vimeo]

En français

2012 R. Vaillant, L. Barthe, G. Guennebaud, M.P. Cani, D. Rhomer and B. Wyvill. "Déformation de la peau d'un personnage avec prise en compte des contacts", Revue Electronique Francophone d'Informatique Graphique, Prix du Meilleur Papier AFIG/EGFR.

Transfer

• Elastic Implicit Skinning: We are working on the commercial development of this technique. All informations here

• Implicit Skinning: Our codes implementing the implicit skinning technique have been available under academic only license from the 17/02/2014 to the 10/11/2014. They are now distributed under GPL3 license. All informations here

• IBL: Our binary composition operators for 3D scalar functions are implemented in the Implicit Blending Library. It is accessible under academic only license. All informations here.

Mediation: Large public and scholars

• "De la sphère à l’animation de personnages virtuels : Pour un Pli", 1024 – Bulletin de la société informatique de France, HS1, pages 93-95, February 2015. All informations here

• Fonctions, formes 3D, assemblages et animation: CIntervention devant les membres du cercle de Mathématiques Sofia Kovaleskaïa à l'Institut de Mathématiques de Toulouse dans le cadre d'une journée CIMI. La présentation intitulée "Fonctions, formes 3D, assemblages et animation" s'adresse à un public d'élèves de première et terminale de bon niveau et vraiment intéressé par les mathématiques. Toulouse 2015. All informations here

• Pour un pli (For a fold): Conference for the large public on the illustration of mathematics taught in high school on recent skinning research results. Poitier 2014, Limoges 2013. All informations here

• Animation movies and 3D video games: from practical to theoretical: Illustration with implicit surfaces and composition operators of the animation of a 3D object defined using middle school mathematics. Scholars in the academy of Toulouse 2012 and 2013. All informations here

Press & Visibility

• 16/11/2016 - RADI 2016: We have been invited to present the "Implicit Skinning" at the "Rencontres Animation Développement Innovation" (RADI 2016) in Angoulême.

• 27/02/2015 - Seminar at Collège de France during Marie-Paule's Cani lecture series.

• 28/10/2014 - Elastic Implicit Skinning - Views of the online Video: More than 5.700 views on Vimeo in less than 5 days !

• 28/10/2014 - Oline Computer Graphics Press: The Elastic Implicit Skinning in CG Press.

• 26/10/2014 - Implicit Skinning - Views of the online Video: More than 25.000 views on Vimeo and more than 120.000 views on Youtube. One of the most seen research Siggraph video.

• 11/09/2014 - CNRS Activity Report 2013: Researches on Implicit Skinning are presented in the CNRS Activity Report 2013 (page 46).