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Adding corrective Shape-Keys

PostPosted: Sun Jan 21, 2018 11:33 pm
by punkduck
Makehuman and the mhx2 skeleton are a good base for posing a character. But we all noticed, that there are some poses which have problems. I will now change one of my characters to work with corrective shape-keys. The normal bones of the skeleton will also manipulate the shape-keys via driver. I must admit, that this topic is rather new for me, but the results justified the work so far.

I started by watching this tutorial, it is rather short and simple to understand:

https://www.youtube.com/watch?v=wUs04SGUnVI

First objects to manipulate are eyelids and eyelashes. Have you ever tried to close the eyes and compare this with reality? The eyes did not really close, you get weird effects (picture on the left side):

problems_with_eyes.jpg


It should look like this:

EyeRegion_Keys.jpg


So we need four shape-keys, two for the eyelids and two for the eyelashes which should be connected to the orbicularis03 bones of the skeleton. We have to create basis and two additional shape-keys for the skin and the eyelashes. To edit the vertices in the final state, select the marked buttons of the armature-modifier of the eyelashes and the skin. Then pose the bone in final position and correct the vertices with the corresponding shape-key selected.

EyeRegion_KeysCreate.jpg


To add the driver you must use the right mouse button over the input field (took me some time to figure that out ;) ) and add the driver (to be created later manually). The driver is setup in the animation screen.
These are only some hints, together with the video-tutorial above you should now be able to do the same. Just a hint: mirroring the shape-keys may fail, because your character may not be fully symmetric.

Here is a very short video (best to be played in slow-motion) to see the bones + shape-keys working:

evi_close_eyes.mp4
(182.31 KiB) Downloaded 176 times


I will add a some information for other shape-keys in future.

Re: Adding corrective Shape-Keys

PostPosted: Tue Jan 23, 2018 10:50 pm
by Mindfront
Corrective shape-keys is unfortunately necessary if wanting that final touch of deformation. At the moment I am experimenting with corrective shape-keys but avoiding doing to many as it is a real pain to reuse them as I soo far only know it is possible to transfer one at a time. But it is possible if the receiving mesh has the same topology. So if i discover I have to change something on my character inside MakeHuman, then I have to transfer all the previous characters shapekeys one by one to the new body.

Re: Adding corrective Shape-Keys

PostPosted: Wed Jan 24, 2018 8:48 pm
by punkduck
Mindfront wrote:But it is possible if the receiving mesh has the same topology.


Sad but true. Evi is "delivered" in 3 versions. One barefoot, one with heel sandals and one with another heel version. Since the geometry is connected, I guess it will not work. What I only can do is to copy the whole character with shape-keys, then chop the feet and replace it by feet with heel sandals. Ooops. Sounds a bit like Dr. Frankenstein. :o

My first idea was to upload these shape-keys. But then I noticed, that I changed geometry for my own proxy - so if I want to do that I've to rework them on a standard character and on a female proxy. Not to forget us males :roll:

Re: Adding corrective Shape-Keys

PostPosted: Wed Jan 24, 2018 10:42 pm
by brkurt
Mindfront wrote:Corrective shape-keys is unfortunately necessary if wanting that final touch of deformation. At the moment I am experimenting with corrective shape-keys but avoiding doing to many as it is a real pain to reuse them as I soo far only know it is possible to transfer one at a time. But it is possible if the receiving mesh has the same topology. So if i discover I have to change something on my character inside MakeHuman, then I have to transfer all the previous characters shapekeys one by one to the new body.


The goal here is maintaining the correct shape of the upper eyelid over the ball, or conversation of mass.
This can also be done with an upperEyeLid bone and weight painting. :geek:

When the upperEyeLid is rotated through the X axis, it can also be pushed into negative Y (a very small change).
I do this with FK only. :ugeek:

If one needed serious close-ups on the eye, you could use three upperEyeLid bones. :o

Why a custom rig versus shape keys? Shape keys lock one into the Blender, a rig can be exported into other apps.
Mostly I need this approach for Marvelous Designer. ;)

Re: Adding corrective Shape-Keys

PostPosted: Thu Jan 25, 2018 3:30 pm
by wolgade
brkurt wrote:When the upperEyeLid is rotated through the X axis, it can also be pushed into negative Y (a very small change).

This is something worth trying. Thanks.
brkurt wrote:If one needed serious close-ups on the eye, you could use three upperEyeLid bones.

And a fourth one as a control bone for the three deformation bones. Oh wait, at this stage it won't be portable anymore. Just like shape keys.

Re: Adding corrective Shape-Keys

PostPosted: Fri Jan 26, 2018 10:42 am
by Mindfront
punkduck wrote:My first idea was to upload these shape-keys. But then I noticed, that I changed geometry for my own proxy - so if I want to do that I've to rework them on a standard character and on a female proxy. Not to forget us males :roll:
I also had the idea of upload an blender-file with my corrective shape-keys, eventually, as I think it can be useful for the community, even though it is a Blender thing and outside MakeHuman.
All my shape-keying is made on an rigged basic exported female mesh, as I liked that most. That basic body mesh is used as an shape-key carrier and also have the weight painting for "Corrective Smooth". Soo far it works for my simply corrections but I guess it had to come sometime when I must do more individual shape-keys.

Re: Adding corrective Shape-Keys

PostPosted: Fri Jan 26, 2018 6:12 pm
by jcpalmer
I was recently going thru the list of Blender add-ons. There is one in the animation category called 'Corrective Shape Key'. Doc button points here.

I have not really done this, but this may help.

Re: Adding corrective Shape-Keys

PostPosted: Mon Apr 30, 2018 11:15 am
by Mindfront
I am about to continue this topic and make a detailed guide how to create corrective shape keys in Blender and how to mirror (I think I have found a working solution to mirror on non symmetric characters) and transfer the shapes to other characters but I wonder if I should post in this thread or make a new in the Tutorials section?

Re: Adding corrective Shape-Keys

PostPosted: Mon Apr 30, 2018 6:29 pm
by wolgade
Posting in this thread might be a good idea to avoid fragmentation of knowledge. There's a lot of it in this forum, but sometimes it's hard to find even if you know what you're looking for.

Re: Adding corrective Shape-Keys

PostPosted: Tue May 01, 2018 9:40 am
by joepal
My preference would be polishing things a bit on the forums, and then when satisfied writing a wiki page about it.

Or simply send me a draft and the images, and I'll put it in the wiki.

This goes for all more elaborate tutorials.