Problems rigging a hip prosthesis for g8f

amelie

I some years ago modeled a left hip-disarticulation prosthesis for V4 for Poser. Now I adapted it to G8F but have problems to rig it correctly:

I updated the geometry of the hip-socket to fit to G8F and then converted it to a prop.

Then I corrected the twist of the thigh and started the transfer-utility with setting the source to current shape.

So far so good. Then i correctly assigned the geometry-parts to the bones of the prosthesis and began to move the bones to fit to the joints of my geometry. 

Here I got the first problem:
First I moved the center-point of each bone to where it should be. This worked good. Then when trying to move the end-points of each bone and snap the end to the center of the childbone, it snapped not to the child but to a "ghost-child", which stayed in position of the original bone-position after using the transfer-utility. It's the position of the bone with the same name from G8F.
When trying to manually move the endpoints into the correct position, the shape of the prosthesis changes unwanted.

Here is my second problem:
After weight-mapping the parts (foot, shin, thigh) of the prosthesis with 100% red for the assigned geometry for hard movement in the joints, I tried to bend the parts with the parameters of G8F because I intend to use walking animations for G8F later.
But then the surprise:
When bending the thigh, also the hip-socket changes shape also there is no weight on the hip and pelvis for the thigh, the thigh-geometry has 100% weight.
So the weight-maps of the G8F seem to have influence to the movment of the tigh of the prosthesis. The same happens with shin and so on.

How can I stop this influence? I want a hard movement of the joints without distorsion of the metal-shapes of the prosthesis or of the rigid plastic-shape of the hip-socket.

picture 1 shows as an example the weight-map of the thigh-bone of the prosthesis and the distorsion of the socket after bending although there is no weight on the socket.
Remember, I didn't bend the thigh of the prosthesis, I bended the thigh of G8F as intended from me.

picture 2 shows a selected bone (thigh-bone). It shows, that the endpoint is not correctly set as I don't know how. As mentioned, snap doesn't work correctly and manual movement moves the bone into another position.

picute 3 shows the distosion of the thigh-metal when bending the shin of G8F

Can anybody give me some hints how to go on to finish my project?

I know, I'm not a good modeller, so sorry for the bad quality of the prosthesis.

Don't be disturbed bei some parts not yet correctly rigged because it makes only sense to do that work, when everything other works fine. I have e.g. to youse the ERC-freece-function for the back-part of the hip-joint.

 

Amelie

Richard Haseltine

For a fitted item the joint centres should be left as the Transfer utlity creates them for bones in the chain - if you don't need to match the base figure then you can use diffrent bone names and set the centres as desired, but having a name match and different centres will cause distortion. Another thing to bear in mind is that the base figure has a lot of JCMs - morphs that adjust the mesh as it is posed - and these will project into the fitted figure unless you create new properties with the name of the JCM that do nothing (or that make chnages appropriate to your model). You can see the JCMs by enabling the display of hidden properties from the Parameters pane option menu, and get the names from the Parameter Settings dialogue launched by clicking the gear icon on the slider.

amelie

Thank you for your answer.

Concerning the JCM's: I made it like in this  tutorial  and baked the JCM's.

But my main problem is, that I have to move the bone-centers to a new location after fitting to G8F. So is there really no way to get rigid prosthesis-parts with bones named as in the G8F? As I told, I would like to get a fitted prosthesis which can be animated together with G8F. So bending G8F's knee should bend the knee of the prosthesis and so on. 

Is it a better way to make new bones after fitting to G8F and then move them automatically by combining them to the movement of the GF-bones by the ERC-freeze-function?

I nevertheless think, it would be more elegant to move the parts of the prosthesis by moving the G8F with identical bone-names.

Amelia

 

Richard Haseltine

I don't knmow that it's impossible, but I would not expect it to work - unless, perhaps, you created a parameter on the base figure which moved its joint centres to the place you wanted the prosthesis' centres and used a wearables preset to trigger that when loading the prosthesis.

amelie

Hello Richard,

 

now I've tried to get a position of G8F, which puts the bone-centers into the position I need the bones for the prosthesis. But I had to stop at the thigh twist bone. Everything I tried, it wasn't possible to bend or side-by-side it independent of the bone "thigh-bend". I toggeled the "override of controllers", toggeled "automatically follows" but it was not possible to place the thigh-twist-bone of G8F in the correct position without also changing the position of the parent bone. But as you perhaps see at my pictures: I need an independent bone for thigh-twist in my prosthesis, which later, in one of the last parts of my work, will be moved by ERC-Freece by bending the thigh-bend-bone. It has to move in a little other way to fit in the back-part of the hip-thigh-joint. By the way, there is a translation in the movement of the upper part of the thigh to the lower part of the thigh, caused by the element in the upper part of the thigh. So the thigh will have three bones. One for the front-part of the upper part of the thigh, one for the back-part (the bone can have every name I want) and the lower part, which is combined at the end with the shin-bone.

It worked with V4 in Poser and Daz and it was much much easier to rig it than now with G8F (or G8F). I'm not lucky, that Daz made it now so difficult to rig attachments for the new figures. But I still hope, I get help here to realize my projects. I already spent hours and hours to try to rig it without effort. It already took me more time than creating the model with zBrush. I'm really frustrated and think about changing back again to poser, but there are not so good and detailed 3D-Figures than in Daz.

So please help me further on. I don't intend to sell this prosthesis. I would give it for free e.g. here or at renderosity when I get it to work.

Amelie

 

 

Richard Haseltine

The bend/twist bones use property-cloning so that you can pose both by selecting only one. I'm not aware of a way to turn that off, all I can suggest is using a new bone and ERC linking it so it still behaves as you want when the figure is posed (though I'm not sure how well that would work).

amelie

Hello,

I already had a working fully rigged prosthesis with other bonenames, controlled by ERC. But this has a problem when trying to use e.g. preset animation-files for walking or when trying to fit shoes, especially shoes with heels. So it would be better to have bone-names as used with the original G8F.

I think, here are some really experienced people who build sellable addons like clothing, shoes and so on. Does really nobody know how to handle this problem? I nowhere found a good tutorial, that rigged attachments like mine.

I perhaps could try to change the shape of my model so it would better fit to the bones of G8F. But to do this, I would need a G8F showing her bones or only the bones in zBrush.

Is there a possibility to export the bones of G8F into zBrush to model a prosthesis so that the joints fit exactly to the bone-centers and ends of G8F? Without seeing the exact positions of the bones in zBrush, it would probanly be difficult to model a prosthesis, where the joints fit exactly.

 

Amelie