Timeline for How get bone X axis for zero roll?
Current License: CC BY-SA 4.0
9 events
| when toggle format | what | by | license | comment | |
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| Jan 25 at 18:35 | comment | added | Salexrock | thanks you very much, i get correct value for all basis vectors by head, tail and roll parameters from blender. unfortunately i can`t set like, reputation need. sorry that I didn't understand your answer right away | |
| Jan 25 at 18:10 | comment | added | Nathan | The X axis of a bone, in that bone's local space, is 1,0,0. The X axis of a bone, in armature local space, is what I've described. | |
| Jan 25 at 18:08 | comment | added | Salexrock | about your latest answer - i need bone local system for desing addon for body dynamics | |
| Jan 25 at 18:00 | comment | added | Salexrock | ok, I need some pause to analyze your answer. | |
| Jan 25 at 17:54 | comment | added | Nathan | Local orientation is armature space. If you want to see tail move, without change in roll or rotation, move in normal Y axis. Movement in armature Y will change the axis of rotation beween it and 0,1,0. But I still think you should focus on the question you want to ask-- if you don't want to do math, don't ask how to calculate the bone roll; if you want to know how to get a bone's axes to point the way you want, ask how to do that instead. | |
| Jan 25 at 17:49 | comment | added | Salexrock | I don't think I understood your answer. But I watched how the roll changes in the blender when the tail position changes - i move tail only along local Y axis, so bone not must rotate. But does. | |
| Jan 25 at 17:30 | comment | added | Nathan | What condition is used to fix the free parameter-- the Y axis-- is that a roll of 0 is what you get when you rotate from the armature Y axis to the bone Y axis, in the cross product of both. But you're probably not asking what you want to ask. You want to know how to set the X axis to an arbitrary direction, without worrying about what roll value to use? Use "recalculate roll" operation in edit mode. | |
| Jan 25 at 17:10 | comment | added | Salexrock | I know how to set the bones to a position with exactly known me values of the vectors of the basis of the local system, but this is not the right way. I can do this for myself, but it will mean that every time before using the procedure will need to make such align for each bone, labor-intensive and incomprehensible for evryone. It`s very wrong resolving. Although the question should be quite simple - to understand what condition was used to fix the free parameter. At first I thought just to position the vector X parallel to the X-Y plane, but not. | |
| Jan 25 at 16:38 | history | answered | Nathan | CC BY-SA 4.0 |