OK...another thrill packed installment of this public diary of animation madness... hopefully, others might find this useful, since the total lack of replies points to a general shortage of knowledge in this area!

Anyway.... I have cured the problem...but I still DO NOT understand exactly what is going on. It is linked to a known issue with extreme rotations of bones, but there is clearly more to it than that!

My camel mod invovled some quite 'radical' re-positioning of the legs, and does some nasty things to the bones, but thats another story

What I found, through trial and error, was that the angle of the lower right rear leg bone was the trigger. I straightened it and the problem went away. OK...I hear you say...we knew that... but explain this...

That leg was rotated 59 degrees....yet the corresponding front leg is rotated 69 degrees with no problem at all. It also only relates to the STARTING point of the bones. There are plenty of bones which rotate a LOT further than that in the routines, with no ill effects at all.

Would love to know why this happens......

Anyway...when I finally complete my animation tutorial, this is all good stuff to add