How to link bones for proper IK attachment?

[Anonymous]

Hello,

I have some models I would like to animate. They come with their proper skin modifier already rigged. However, the bones are somehow not linked together making the animation mostly impossible under my knowledge.

I've been trying to link these bones to apply a IK solver, but each limb from the model uses two bones. I can't seem to link properly the bones because of this. Also, if I try to group the two bones per limb into one group, I'm unable to apply a IK solver. I don't want to create a new skeleton, since I would lose all the rigging information.

Here I leave my model:

https://drive.google.com/open?id=0B3S5M3C7LLkBVnlOZzR4eUxFQzA

If anyone knows how I could manage to utilize these bones to properly animate my model, I would highly appreciate. 

[silentboof · Accepted solution]

Well proper bone placement and applying IK and such, can take a long time to explain so you need to watch some tutorial about the subject but there are things you can do to animate you character easily.

Simply create a biped or a predefined CAT system and try to reposition let's say the biped bones properly based on your model bones and match them as closely as possible and then link the original bones to the biped bones.Now when you animate the biped your character will be animated as well. Also make sure all the bones in you character has NO link to any abject before linking them to biped bones.

[Anonymous]

Hi pablorodrigueza,

another thing you should give a try is to deactivate the checkbox in one of the rollouts labeled "Always deform" and the skinmodifier in the stack. You then can modify the rig as you like and activate the checkBox and the modifier again. Of course you need to be in skinpose to do this, otherwise your mesh will not match the bones any more. If this doesn't work directly try playing around a little - basically this option can help you in this situation.

Hope this helps you,

Martin

[Anonymous]

Thanks, by using and linking the biped to the bones I was able to animate my model and it works great!

I have encounter another issue with these models. I am trying to fix the normals by unifying them, but when I do I loose the smoothness in the model. I tried to apply a smooth modifier, but it has no effect.

[silentboof]

Apply an "edit poly" modifier.(don't turn it into editable poly just apply a new modifier) and make sure it's under the skin in the stack. That should smooth thing out. If not not, apply a smooth modifier on top of it and turn on "auto smooth".

Just to clear things out: your modifier stack should look like this:

|  skin                  |

|  smooth            |

|  edit poly          |

|  editable mesh  |

[Anonymous]

I tried that, but whenever I apply a modifier on top of the Editable Mesh everything turns faceted and can't get it smooth again. Is there any other way of fixing the normals?

[silentboof]

Well copy the skin modifier and collapse everything and try to fix the object as editable poly; after you are done, you can paste the skin again. If the problem persists You can upload your scene n I'll check it to see what's the problem. (I'm using max 2016; if you have a higher version installed, save the file as 2016).

[Anonymous]

Doesn't seem to make a difference either. I leave the scene here, I am using 3D MAX 2013.

[silentboof]

Ok the model's a mess!!! The main issue is about the faces! They are all elements so you need to weld vertices. Apply a "vertex weld" modifier with a low threshold n then a smooth modifier.But still you loose some smoothing groups (e,g cloth wrinkles). In the source program make sure you export it as a single object or in the import dialogue look for an option for welding the vertices and keep the smoothing group.

I fixed two objects in the right leg; you just need to copy n paste the modifiers as instance, on the rest.

[Anonymous]

Thanks, that did the trick. If only the vertex welding could take the whole shape in consideration would be great, but I'm pleased with the results so far. Many thanks!

[silentboof]

you're welcome.

about welding the whole character well I think you can do something about it.

follow this procedure carefully:

1. clone all the body part
2. turn them into editable poly ( the cloned objects loose their skin modifier)
3. attach all the cloned objects together (now you have on single geometry)
4. weld all the vertices (now you don't have any unwanted element)
5. match the single geometry to the original body parts that still have their skin modifier
6. apply a skin wrap modifier and add all those original geometries (make sure weight all points option in enabled before adding anything)
7. wait!!!   (there are too many objects and I guess It takes some time)
8. now click on convert to skin
9. the skin wrap will be off and a skin modifier will be added to the stack automatically (now you can even delete skin wrap)
10. you may delete all those extra body parts.

let me know if that works cuz something came to my mind n right now I don't have access to max to test it out....however, logically it should work! 

[Anonymous]

I'm having trouble with step 5. I can't seem to match the single geometry to the originals. Do I have to detached?. If so, how can I be certain I'm doing it right?

[silentboof]

check out this video I just captured:

[Anonymous]

Thanks, it was actually easier than I thought. One last thing, If I wanted to keep the smoothness and the correct normal, but all in separate figures, like it was in the original character, is it possible? Because I tried and the normals rearranged when I detached and separated the figure.

[silentboof]

yeah sure...just don't apply "edit poly" modifier and you're good to go