Interpolation between two shapes

 

(1) The following examples 1-4 are interesting test data for evaluating shape interpolation method. These test data sets are interesting, since their poses vary with different degrees. From our point of view, the degree of difficulty in these data sets is example 1, 2, 3 and then 4 in an increasing order. For example, in example 1, if you globally align poses of two models and then do shape interpolation, the result can be improved. However, in example 3 and 4, it may be difficult to handle using a single global alignment. In addition, we also implement a Poisson shape interpolation method [1] to experimentally compare our results. Follow each link and you can see video or get models to test your method.

 

(2) Hope this web site serves as a test platform to compare different shape interpolation methods. Welcome your contribution and test your method. Please send your results to us. Later, we may design more challenging cases if necessary. Note that our method use shape variation information to assist shape interpolation. Our mesh reconstruction part use gradient-based method [2] and [1] used [2], too. So, we currently compare our method [1] for this study. Other mesh reconstruction can be used instead such as volume-preserved method etc to preserve volume.

 

(3) Contributors

 

l         Prof. Tong-Yee Lee (for this web site)

 

l         Dr. Niloy J. Mitra and Martin Kilian, see their tested results using their method in SIGGRAPH 2007 [3].

 

 

Example1:

(a) Video created by our method

Description: A lion shape (9996 faces) from a stretched pose to a curled pose. Limbs and tail are bended naturally toward the target pose.

Input:

source obj

target obj

 

Several frames in above video are shown below. Note that source and target shapes are rendered in red color.

 

(b) For simple comparison, we generate results (Video) using Poisson shape interpolation [1].

 

Several frames in above video are shown below. Results are not good (due to variation of pose orientation).

 

(c) Align the target shape with source one manually and use [1] to generate result (Video).

Input:

The same as above

target obj

Illustration

 

Several frames in above video are shown below. With rough global shape alignment, [1] can generate better result, but still has some defects (see the tail of lion). However, the orientations in this sequence are wrong in contrast to (a). The same problem happens to the following 3 examples.

 

Example2:

(a) Video created by our method.

Description: Interpolation between two curled poses with near pi rotation of the body.

Input:

source obj

target obj

 

Several frames in above video are shown below.

(b) For another simple comparison, we generate results (Video) using [1].

  Several frames in above video are shown below. Results are not good (due to variation of pose orientation).

 

(c) Again, we manually align the target shape with source one and use [1] to generate result (Video).

Input:

The same as above

target obj

Illustration

 

Several frames in above video are shown below. Notice the defects appear in the tail and right-back limb.

 

Example3:

(a) Video created by our method.

Description: Shape interpolation of a male shape (34970 faces) from a stretched pose into a crouched pose. Notice the natural bending of the body, limbs and fingers, and the preservation of the local details (lines of the muscle) during the interpolation. To test verify your results, you may check if fingers can change its pose smoothly in your result.

Input:

source obj

target obj

 

Several frames in above video are shown below.

 

(b) Another interpolation result (Video) shows the comparison with [1].

 

Several frames in above video are shown below. The defects (left-fore arm and all fingers) appear due to the same reason (wide pose variation).

 

(c) With the aid of global shape alignment, [1] generates better result (Video), but the still fails in finger parts which represent highly articulated structure.

Input:

The same as above

target obj

Illustration

 

Several frames in above video are shown below.

 

Example4:

(a) Video created by our method.

Description: Another example of male¡¦s shape interpolation. In this example, the pose is varied significantly in body¡Blimbs and fingers and is the most challenging one in our experiments.

Input:

source obj

target obj

 

Several frames in above video are shown below.

 

(b) Interpolation result (Video) of [1].

 

Several frames in above video are shown below.

 

(c) (Video): Even with the aid of global shape alignment, the improvement to the result of [1] is little. We believe that the more the complexity of the articulated structure of the shape the difficulty of the pose interpolation will be increased.

Input:

The same as above

target obj

Illustration

 

Several frames in above video are shown below.

 

Reference

[1] Dong Xu, Hongxin Zhang, Qing Wang, Hujun Bao. Poisson Shape Interpolation. ACM Symposium on Solid and Physical Modeling, 2005

[2] YU, Y., ZHOU, K., XU, D., SHI, X., BAO, H., GUO, B., AND SHUM, H.-Y. 2004. Mesh editing with Poisson-based gradient field manipulation. ACM Trans. Graph. 23, 3, 644.651.

[3] Martin Kilian, Niloy J. Mitra, Helmut Pottmann, Geometric Modeling in Shape Space, ACM SIGGRAPH 2007.