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Known Softimage|3D bugs which affect Falling Bodies

Rescaling flexible envelopes (Softimage|3D Bug #6994)

There is a known problem with changing the scale of  models with skin in Softimage|3D. This problem is present in all versions
of Softimage|3D up to at least 3.8SP1. In 3.8, a workaround exists. This workaround can be enabled by setting the environment variable SI_INIT_POSE_COMPENSATE to 1. This is done as follows, on Windows NT 4.

Turning on the workaround [NT 4 / SI 3.8 only]

First, exit Softimage|3D if it is running. Then start Softimage User Tools from the Windows menu Start->Softimage Products->Softimage3.8->User Tools.

User Tools dialog

Select Environment Script and click on Edit File to get the following dialog.

User tools editor screen

Add the new line set SI_INIT_POSE_COMPENSATE=1 as shown. Then click Save and Close.

Background information

This workaround should fix the problem for new models created after this fix is enabled. Models created before this fix may
have problems. A good way to check, after installing this fix, is to load character models created before the fix,
rescale some parts of the character and then do Actor->Skeleton->Reset. The envelope should  be in the right place relative to the skeleton. If it fails this test, the model should never be rescaled, and may have problems with Falling Bodies.

This problem is related to the Reset Actor problem described in the Softimage knowledge base. Setting SI_INIT_POSE_COMPENSATE seems to eliminate that problem as well.

Scaled versions of the same model
With this fix in, you can rescale skeleton parts of an enveloped character, making the legs thinner or the torso longer, and the envelope will be adjusted accordingly. This is an easy
way to make variations on an existing character. The two characters on the left were created that way. Without this fix, attempts to rescale skeleton parts yield a broken model, with the skeleton and envelope no longer matching.

Softimage/Avid informs us that they are reluctant to turn on this fix for all users without further testing, which they are not willing to do at this time. So some caution is indicated in using this fix. It seems to be safe for new work, but there is a possibility of incompatibility with old scenes. At worst, the envelope and skeleton get out of sync when an old character is
animated. We have seen this only when the character couldn't survive Actor->Skeleton->Reset before the fix, which indicates the
model already had problems.

We've been running with SI_INIT_POSE_COMPENSATE=1 for most of 1999 without problems. If you do find
a problem with this, please let both Animats and Softimage support know.

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June 21, 1999