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View Full Version : Exactly how does Bone Twist Work?



spec24
02-13-2005, 12:37 PM
It only appears to rotate my bank and nothing else. What good is this? The heading and pitch stay exactly the same. I know it's supposed to work, but it doesn't now.

Dodgy
02-13-2005, 06:00 PM
Bone twist will show up in the Heading and pitch handles of the bone BELOW the bone you are twisting. This is because LW works in Parent coordinates. If you switch to local coordinates you'll see the twist reflected in the bone you twisted.

spec24
02-14-2005, 07:36 AM
Bone twist will show up in the Heading and pitch handles of the bone BELOW the bone you are twisting. This is because LW works in Parent coordinates. If you switch to local coordinates you'll see the twist reflected in the bone you twisted.

I'll try that tonight. Thanks Dodgy.

spec24
02-15-2005, 07:39 PM
Nothing. No change except for the direction of translation arrows. The pitch and heading stay exactly where they were.

spec24
02-16-2005, 06:17 AM
also, when I create skelegons in modeler I create all of them in the same viewport so that the pitches will all be aligned. But when I convert to skelegons in layout the parent bone is always in the wrong orientation. It's heading is where the pitch should be and then all the children bones have their pitch correct. IF this didn't happen I wouldn't need the bone twist. However since I can get neither to work this craetes problems. Can anyone tell me how to get these processes to work? It's really aggrivating.
Dodgy - no matter what coordinate system I'm in, the bone I'm twisting does not twist.

Dodgy
02-16-2005, 06:34 AM
also, when I create skelegons in modeler I create all of them in the same viewport so that the pitches will all be aligned. But when I convert to skelegons in layout the parent bone is always in the wrong orientation. It's heading is where the pitch should be and then all the children bones have their pitch correct. IF this didn't happen I wouldn't need the bone twist. However since I can get neither to work this craetes problems. Can anyone tell me how to get these processes to work? It's really aggrivating.

For this part use Edit Skelegons in Modeler>Setup to check the bank handle's orientation. It might be off to one side, so rotate it in the top view to be aligned with the z-axis. This will solve the problem when you convert them in layout.


Dodgy - no matter what coordinate system I'm in, the bone I'm twisting does not twist.

It definitely works for me. When you've done the twist, have you pressed y to change to rotate mode, and pressed shift+f7 to go into Local coord mode?

spec24
02-16-2005, 06:53 AM
It definitely works for me. When you've done the twist, have you pressed y to change to rotate mode, and pressed shift+f7 to go into Local coord mode?

you mean press 'y' AFTER I've clicked on the bone twist tool? I didn't do it exactly like you described - I had clicked on the bone and then changed the coordinate system, then clicked bone twist and then twisted :) When I get home I'll try your method. This work is really an inconvenience :)


all the handles looked to be in the right orientation in Modeler. But I'll take a closer look.

Vailias
02-16-2005, 11:06 AM
The modeler orientation handles are local coordiants to the bone itself, and so if you need to use things in layout like rotation limits or expression and such they won't apply like you think because the bones still and their properties still use parent coordinants.

Depending on your setup what you may be able to do is create a disjointed heirarchy of skelegons then parent each segment/bone where it belongs manually in layout to get the motion you want, as this will avoid oddly oriented "connector" bones.

Dodgy
02-16-2005, 05:24 PM
I think you'll find the root bone's handle will be pointing out to the x-axis, for some reason it switches to this when you draw the second bone. I think it's a bug :P I'll report it.

spec24
02-17-2005, 05:08 PM
okay - so let me get this straight. I can rotate the parent bone in Parent Coord system but that doesn't actually rotate the parent bone - it rotates the child bone and the child bone's pitch changes. If I switch to Local Coord then I can rotate the Parent bone and it's pitch can be aligned to..... nothing. That rotation only affects the coord system in the local system. When I switch back to the Parent coord system the bones are still unaligned - the pitch of the parent bone has stayed exactly the same. But since we don't animate in Parent coord system I fail to see any use for this. Maybe I'm missing something still. I thought I had done this before and got it to work as expected. But for the life of me I can get it to work in any rational way - so far there is no way I can align the parent bone's pitch in the direction I want it to be.

Dodgy
02-17-2005, 06:05 PM
Okay, what you do is choose the bone whose pitch you want to alter. Then you select the PARENT of that, and use Bone Twist on it till its 'pitch' is in the direction you want. This will align the pitch of the actual bone you want to modify correctly.

spec24
02-17-2005, 06:24 PM
ok - what if the bone who's pitch you want to alter is the root/parent bone of the whole lot? In fact when I do a bone twist on the root bone (the parent of all of them) - the whole skeleton filps sideways and the root bone changes it's orientaion.

also - was I missing something? On the newtek video showing this tool that is not what he did. He selected the bone he wanted to twist and it worked. Must he have been in Local mode?

I really appreciate the help Dodgy.

SplineGod
02-18-2005, 01:47 AM
Bone handles in modeler are created perpendicular to the viewport you draw the skelegons in. This is important to remember or else youll have to tweak a lot of bank handles if you draw from the wrong viewport. This isnt the case when drawing bones in layout which is much easier IMO.

Also since LW uses a parent based coord system the bank handle on the skelegon that youre tweaking is affecting the pitch of the child. The bank handle and skelegon determine the pitch plane. Bone twist works the same. If you use it in parent coord mode it behaves like bank handles in modeler ie. the twist tool on the current bone is affecting the pitch of the child. If, however youre in local mode, youre affecting the pitching of THAT bone, BUT you have to run the Record Pivot Rotation tool right after (shift + p).

The purpose of all this is to get the pitch oriented in the right way to take advantage of joint compensation and muscle flexing. If you dont care about those then it really doenst matter. :)

spec24
02-18-2005, 06:43 AM
Bone handles in modeler are created perpendicular to the viewport you draw the skelegons in. This is important to remember or else youll have to tweak a lot of bank handles if you draw from the wrong viewport. This isnt the case when drawing bones in layout which is much easier IMO.

Also since LW uses a parent based coord system the bank handle on the skelegon that youre tweaking is affecting the pitch of the child. The bank handle and skelegon determine the pitch plane. Bone twist works the same. If you use it in parent coord mode it behaves like bank handles in modeler ie. the twist tool on the current bone is affecting the pitch of the child. If, however youre in local mode, youre affecting the pitching of THAT bone, BUT you have to run the Record Pivot Rotation tool right after (shift + p).

The purpose of all this is to get the pitch oriented in the right way to take advantage of joint compensation and muscle flexing. If you dont care about those then it really doenst matter. :)

yes but if you twist the bank handle in modeler the actual bone you're twisting is affected - not so in Layout - unless you're in Local mode which seems useless to me. I'll try running the record pivot rotation right after doing the bone twist (sounds like a dance) tonight. Thanks! :)

SplineGod
02-18-2005, 10:30 AM
yes but if you twist the bank handle in modeler the actual bone you're twisting is affected - not so in Layout - unless you're in Local mode which seems useless to me. I'll try running the record pivot rotation right after doing the bone twist (sounds like a dance) tonight. Thanks! :)

Lets say you have 3 skelegons in a parent/child hierarchy. If you select the bone handle on the first skelegon it is affecting the pitch on its child (skelegon 2).
This is because LWs coord system is parent based which means the orientation of the parent determines the orientation of the child and so on.

This is exactly how the twist tool works in layout IF you are in parent coordinate mode which is the default. This means that the bone you run bone twist on is changing the pitch for its child UNLESS you switch to local mode.