Abstract of our papers

New bending method for 3DCG

SBS+method is the very effective method that achieves skin animation with only a small number of distortions. This method has been utilized for some major three-dimensional skin animation software and the three-dimensional model utilizing this method has become part of the main stream of such software. However, although its concept and effectiveness are shown, its algorithm and specific implementation method cannot be said to be publicly known, and there are many unclear portions of its behaviors. If these become clear, further development of the three-dimensional skin animation software technology can be expected. In this paper we formulate SBS+ and show the implementation, which has the same behaviors as those of other major three-dimensional skin animation software, and analyze such behaviors, examine the problematic points and make clear such unclear portions through experiments. Furthermore, we propose new implementation cases and show that it is possible to achieve more natural transformation than with conventional software in the paper. The major parts of the program source codes used in this paper are available from our website.

TPS suited for morphing the joints of a 3D polygon model

TPS suited for morphing the joints of a 3D polygon model

Although TPS is a suitable technique for morphing a 3D model, the processing speed is slow.
A scheme using TPS to morph the joints of a 3D polygon model was studied.
By performing local processing based on the distance, it is shown that high speed and adequate morphing can be carried out.
When morphing the joints of a 3D polygon model, an enormous number of control points exist.
The number of targets is relatively small.
The position of the control point involved with the morphing coefficient is local.
A distance-based local control point is selected for each target.
The coefficient can be calculated based on this.
In this method, the respective morphing coefficient needs to be determined for each target.
However, in the scheme for morphing the joints of a 3D polygon model, the number of applicable peak points is small.
Therefore, this method has a higher processing speed than general methods.
This fact is demonstrated empirically.
Compared to the results with general methods, this method results in almost the same peak.
This method is precise enough to be used for the joint deformation in a 3D polygon model.
When this method is applied on two types of model, the processing speed was 33.0 and 331.3 times faster, respectively, demonstrating how useful this method is.

Shrink wrap automation using bone alignment and skeleton

We propose a new shrink wrap technique to reduce the effects of misalignment between models, which is a problem when shrink wrapping objects with complex shapes.
After aligning using a bone for the purpose of regulating the movements of the 3D model, the shrink wrapping is carried out using the skeleton of a mathematical morphology.
Furthermore, we also propose a method for reducing inappropriate deformation of the model when using this technique in actual practice.
Shrink wrapping is a useful method often used in the design of clothing put on a living model. Many conventional methods have their own advantages and disadvantages therefore different methods need to be used for different purposes. We looked into the method of using a morphological skeleton as a means to resolve this. This technique allows the shrink wrapping of complex shapes which can give rise to inappropriate shrinkage in conventional techniques.
However, this technique faces a problem of having to manually align the models precisely.
This paper proposes a method of performing the alignment automatically.
Since simple alignment may result in inappropriate shrinkage instead, the alignment is performed sequentially from the dense to the sparse sections of the bone.
Even if shifting occurs in the sparse section, this is not conspicuous, making it possible to reduce inappropriate deformation in the model. In order to verify the effectiveness of all these, we compared this technique with conventional techniques via experiments. The results showed that this technique is effective in reducing inappropriate shrinkage.