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The Artist Synapse Back to Intro |
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Example Artist Interaction: Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 |
| Degrees of Separation [View] |
| Psychology [View] |
| Suggestions [View] |
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Features vs. Beauty [View] |
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Artist: What kind of polygons
are supported? Producer: Convex planar polys are supported. |
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| Tech: The usual answer to this simple question is either "Only tris [three-sided polygons] are supported," "Quads [four-sided polygons] and tris are supported," or "Convex planar polygons with any number of sides are supported." When tris are used, geometry doesn't have to be planar and convex. This type of geometry is easier for the artist to work with, but requires more tris to build a model. Quads and n-sided polygons must be planar and convex, but fewer polygons are necessary to construct planar objects. | |
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Artist: How are the polygons
created from tris? Producer: If two tris share an invisible edge, they will be merged to a quad. |
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| Tech: This is a pretty standard solution to the problem that some modeling tools have, most notably 3D Studio MAX and 3D Studio 4.0. The problem is that the tools don't directly support any polygons besides tris. Our hypothetical programmer's solution isn't the only way to merge tris into polygons. For instance, sometimes a part of the art import procedure accepts a 3D data file, looks for coplanar tris that share edges, and replaces them with polygons. | |
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Artist: What tolerance, if
any, is used when deciding that a quad isn't planar? Producer: One degree or less out of plane is O.K. |
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| Tech: This question applies if the import procedure has the ability to accept slightly noncoplanar quads as coplanar. This can save a lot of unnecessary editing, since it's common during normal construction for some faces to be slightly noncoplanar; it's difficult to make all faces perfectly coplanar. | |
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Artist: Are T-intersections
allowed? Producer: Yes. |
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| Tech: The most difficult aspect of this question is agreeing on what a T-intersection is. As Figure 1 shows, T-intersections occur when one face touches another face, either in the center or at an edge, without sharing all vertices. If the answer is "no," the artist needs to understand the consequences because sometimes T intersections are almost impossible to prevent. |
 Figure 1 |
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Artist: Are intersecting faces
allowed? Producer: Yes. |
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| Tech: This question may be asked instead of the sorting question that follows, but an understanding of the various sorting options is preferable to a simple yes or no answer on intersections. Be sure that the programmer agrees on the definition of "intersecting faces." What artists generally need to know is whether two faces can cross each other, forming a line (or a plane if they are coplanar) of intersection. | |
