Inflatable Icons: Diffusion-based Interactive Extrusion of 2D Images into 3D Models

Alexander Repenning
AgentSheets Inc.

This paper appears in issue Volume 10, Number 1.
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Abstract

There are many applications, such as rapid prototyping, simulations and presentations, where nonprofessional computer end-users could benefit from the ability to create simple three-dimensional models. Existing tools are geared towards the creation of production quality three-dimensional models by professional users with sufficient background, time and motivation to overcome steep learning curves. Inflatable Icons combine diffusion-based image extrusion with a number of interactively controllable parameters to allow end-users to efficiently design three-dimensional objects. Early user testing has indicated that it takes end-users, even kids, just minutes to draw icons and then use the Inflatable Icons approach to create three-dimensional models which they can use to build video games.

Author Information

Alexander Repenning, AgentSheets Inc., 4565 Gunpark Drive, Boulder, CO 80301

Figures

The following are the figures from the paper. Click on a thumbnail to see a higher-resolution version.

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Figure 1. A low-resolution icon ready to be inflated.

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Figure 2. Each pixel is polygonized with two triangle polygons.

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Figure 3(a). Inflation: Icon is still flat

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Figure 3(b). Inflation: Icon starts to inflate

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Figure 3(c). Icon is fully inflated by biased diffusion

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Figure 4. A flat-shaded inflated icon.

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Figure 5. Gouraud-shaded inflated icon.

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Figure 6. A circle icon with visible aliasing (left). The inflated icon (right) has a smooth surface but keeps the aliased edge.

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Figure 7. The "bad" aliased part of the inflated icon is cut away with a clipping plane (left) to get a smoot edge (right).

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Figure 8. The sharp edge at the bottom of the heart gets lost in the antialiasing.

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Figure 9. A general inflation turns a teddy icon (left) into a noncompelling inflated icon (right).

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Figure 10. Black pixels have more pressure; white pixels have less pressure.

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Figure 11. A grey blob (left) turns into a balloon (right).

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Figure 12. Noise added to the balloon makes it look like a sponge and not like a rock.

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Figure 13. Two iterations of diffusion (left) and three iterations of diffusion (right) applied to the sponge create a rock look.

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Figure 14. A simple user interface to inflate icons.

Movie

Here is a short movie illustrating icon inflation: Inflatable Icons Movie (1.4M).

Errata

  • The printed paper is missing the following acknowledgement:

    This material is based in part upon work supported by the National Science Foundation under Grant Numbers NSF OII/ENG 0349663, and NSF ITR/PE 0205625. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

BibTeX Entry

@article{Repenning05,
  author = "Alexander Repenning",
  title = "Inflatable Icons: Diffusion-based Interactive Extrusion of 2D Images into 3D Models",
  journal = "journal of graphics tools",
  volume = "10",
  number = "1",
  pages = "1-15",
  year = "2005",
}