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ID Category Severity Reproducibility Date Submitted Last Update
0000467 [Croquet] Jasmine minor always 10-27-04 18:11 11-10-04 01:06
Reporter rstewart View Status public  
Assigned To Croqueteer
Priority normal Resolution fixed  
Status resolved  
Summary 0000467: Distortion of spinning sphere
Description If you get an object spinning, and let it go for several hours (or overnight), then object will become distorted over time. In the case I was working with, I created a sphere (as an ase), and loaded it into my space as a TSpinner, then started it spinning. After several hours, it gets distorted to a disk. Is there a rounding error here?
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- Notes
(0000542 - 495 - 495 - 495 - 495 - 495 - 495)
Croqueteer
10-27-04 18:19

In a word - yes. What is happening is we are creating the new transform by multiplying the last one by the delta rotation transform. This will cause a build-up of error in the resulting transforms. The correct way to do this is to maintain the current rotation values and reconstruct the transform matrix. I think it is not that much different in cost to just do this everytime, but if not, then just do it every 100 transforms or so. I wrote this code, but wasn't thinking about it at the time.
 
(0000650 - 297 - 309 - 309 - 309 - 309 - 309)
Croqueteer
11-10-04 01:06

This fixes a problem with using the previous transform matrix composed with a new matrix. Over time, these matrices have a tendency to deform unless they are renormalized.

First added a new #normalize method, then applied this every so often... make sure this is done deterministically, duh...
 

- Issue History
Date Modified Username Field Change
10-27-04 18:11 rstewart New Issue
10-27-04 18:19 Croqueteer Note Added: 0000542
11-10-04 01:06 Croqueteer Status new => resolved
11-10-04 01:06 Croqueteer Resolution open => fixed
11-10-04 01:06 Croqueteer Assigned To  => Croqueteer
11-10-04 01:06 Croqueteer Note Added: 0000650


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