Xfrog Library Checklist

Timm Dapper (td@td-grafik.de)
last change: (05/28/2003)



Do only use aplhanumerical characters and underscores in Component Names. No Special Characters (e.g. '.', ';', ':', '-', '/') and Spaces in Copmonent Names. Also ensure that Component Names do not have more than 15 characters.

Make sure texture filenames also fit the above rule and additionally only use the old DOS convention for filenames (never more than 8 characters name, 3 characters extension).

Ensure the last keyframe (which is always automatically generated at the end of the animation) is identical to the first. Otherwise some strange animation might occur within the PlugIns if the user doesn't explicitly disable animation (e.g. the whole model transforming to the Hierachy with default parameters applied everywhere).

Ensure no Parameter Value is outside the Range specified in the GUI. Parameter Values outside the specified range may cause models to act strange. For animations also take care that values don't fall out of the range in the course of the animation. This is a bug/strange behaviour in Xfrog, but library models shouldn't do this anyway since it's bad style.

Tree Component Scale
I've encountered numerous models in the libraries which for some reason use tree components with their scale set to zero for the last third of the tree. This habit should be abandoned and models containing that should be changed on the long run! It produces an unnecessary amount of geometry (since the geometry of the last third is still created, it's just too thin to contribute to the image). This has siginificant negative impact on Level of Detail as well. There are additional side effects, the models are strange to handle (they don't behave like expected), bounding volumes are far bigger than necessary (which makes handling the model less efficient & will make usage of other Components like the HyperPatch unintuitive). This is especially a problem when people try to modify those models or try to learn from them.

Keep your Hands off the Growth Scale (new)
The Growth Scale should only be touched very carefully. Growth Scale should not be used for modeling because it will greatly limit the user he wants to use the parameter for growth animation later on. The Problem is basically that every point on the growth scale spline should be lower than all the points on its left, otherwise you'll get funny effects. Walli had this problem with a cupressus tree a few weeks ago, perhaps he can let us know again which model this was so you (orio) can just play around with the Trunk Scale and see what happens, this is probably better than trying to describe the problem over several pages. I don't want to forbid anybody to use this parameter, I'd just advise only to use it as a last resort when nothing else will do the job.

Texture Size
Use Power of 2 sizes (256x256, 512x512, 1024x1024, etc.) and only uncompressed tiff for textures. This will make sure that each and every application can read and get the best out of all textures.

Texture Names
Make texture names as unique as possible (even across different libraries), as they may all be in texture searchpaths together and when they have identical names (such as "leaf.tif", "bark.tif") the host application can get confused.

Texture Alpha
Use Premultiplied Alpha Textures (see here for more info).

Color Settings
Do not use the Emission and Alpha Settings at all. Trees don't emit light and using this setting to make trees look nice in Xfrog will cause major trouble when importing into other Applications.
Try to choose values that make good sense for diffuse. Keep in mind that the Texture Color is getting multiplied with the diffuse Color. This is good for giving a texture a certain tint, but it may also darken textures when not set to white. Also be aware that Lighting in Xfrog is usually slightly brighter than it will be in many major applications.
Don't use Ambient Color too much, especially not for coloring as this does not translate very well to many applications.