Skin modifier problems
by Bhood · in Artist Corner · 10/18/2005 (12:06 pm) · 8 replies
Hi there,
I'm having a really hard time with the 3DS 6 skin modifier... have tried various approaches i.e. using Biped, Skeleton from Girl Pack and creating bones using the Torque Skeleton Creator... my problems happen with any and all of these approaches when I add the skin modifier...
So, I add the skin modifier to my mesh, select bones and then every time, the whole body will move with the skeleton but not bend at any joints etc. To get any sort of bends I have to start a long and messy process of 'Edit Envelopes'. So, I've then been selecting vertices, selecting relevant joint from the list and changing the Weight Properties: Abs Effects, generally having to set the value at somewhere between 0.2 and 1 to get any effect. I've just tried to do a bit of an overlap, with vertices assigned to more than one joint but it's still one hell of a mess, huge distortion as soon as I move any joints, basically unusable.
Am I going really wrong somewhere? I saw a comment in another post that there's little difference in how the physique and skin modifier works but at the moment I really wish I could use physique for this. I've tried applying that and things are fine, everything moves pretty fluidly with the biped!
Any tips would be so appreciated, this is driving me bonkers!
Thanks,
Bev
I'm having a really hard time with the 3DS 6 skin modifier... have tried various approaches i.e. using Biped, Skeleton from Girl Pack and creating bones using the Torque Skeleton Creator... my problems happen with any and all of these approaches when I add the skin modifier...
So, I add the skin modifier to my mesh, select bones and then every time, the whole body will move with the skeleton but not bend at any joints etc. To get any sort of bends I have to start a long and messy process of 'Edit Envelopes'. So, I've then been selecting vertices, selecting relevant joint from the list and changing the Weight Properties: Abs Effects, generally having to set the value at somewhere between 0.2 and 1 to get any effect. I've just tried to do a bit of an overlap, with vertices assigned to more than one joint but it's still one hell of a mess, huge distortion as soon as I move any joints, basically unusable.
Am I going really wrong somewhere? I saw a comment in another post that there's little difference in how the physique and skin modifier works but at the moment I really wish I could use physique for this. I've tried applying that and things are fine, everything moves pretty fluidly with the biped!
Any tips would be so appreciated, this is driving me bonkers!
Thanks,
Bev
#2
In regards to how to work with the Skin modifier in Max 6 (please don't refer to it as 3DS as 3DS is/was a completely seperate product that predates Max and as such it makes it easier to provide help if you name your application correctly)...
1) Add all necessary bones or control nodes to the "bones" list in the skin modifier
2) Adjust the envelopes as necessary. The key thing here is that it doesnt need to be exactly accurate, a quick and dirty setup is just fine, you only need to make it good enough so that the envelopes are influences what they need to influence. ie) arm bones are only enveloping the arm and not the thigh or chest for example.
3) Use the paint weights tool to tweak how a bone will influence a vertex. This is pretty slow and tedius but its where you need to spend a lot of work getting the deformations just right and can cleanup any problems from the evelopes. Also as Magnus suggested this area is where its great to use the Mirror tools built into the skin modifier to mirror weights from one side of the mesh to the other it is indeed a time saver.
Note: With Max 7 and more specificly Max 8 this work flow is greatly improved to the point where it takes no time at all to skin a character.
Also as Magnus says go look for the Physique <--> Skin utility on sparks.discreet.com as it will allow you to move your data between a Physique modfier and a Skin modifier.
10/18/2005 (12:30 pm)
Actually there are huge differences with regards to Physique and Skin with regards to how they work and their development. Physique is pretty old and doesn't get much attention, it works off of deforming your shape based on the joints between two bones. Skin is an ultra fast and sexy solution that is constantly being refined and enhanced and ususes actual bone transforms to drive the vertex deformations. Each one has their own benefits and problems though for the most part Skin really does beat Physique hands down.In regards to how to work with the Skin modifier in Max 6 (please don't refer to it as 3DS as 3DS is/was a completely seperate product that predates Max and as such it makes it easier to provide help if you name your application correctly)...
1) Add all necessary bones or control nodes to the "bones" list in the skin modifier
2) Adjust the envelopes as necessary. The key thing here is that it doesnt need to be exactly accurate, a quick and dirty setup is just fine, you only need to make it good enough so that the envelopes are influences what they need to influence. ie) arm bones are only enveloping the arm and not the thigh or chest for example.
3) Use the paint weights tool to tweak how a bone will influence a vertex. This is pretty slow and tedius but its where you need to spend a lot of work getting the deformations just right and can cleanup any problems from the evelopes. Also as Magnus suggested this area is where its great to use the Mirror tools built into the skin modifier to mirror weights from one side of the mesh to the other it is indeed a time saver.
Note: With Max 7 and more specificly Max 8 this work flow is greatly improved to the point where it takes no time at all to skin a character.
Also as Magnus says go look for the Physique <--> Skin utility on sparks.discreet.com as it will allow you to move your data between a Physique modfier and a Skin modifier.
#3
thanks for your replies. Even more support for the Skin modifier approach so I really must get this sorted!
Can I backtrack a moment to expand on both your comments about "adjusting envelopes"? i.e pre- Abs Effect adjustment or Step 2 in second mail? Please could you clarify how exactly you go about this?
Perhaps I have been jumping ahead a step? You see once I've applied the skin modifier I'm going straight to 'Edit Envelope' button, checking 'Vertices', selecting an area of vertices and then selecting a bone from list and changing Abs Effect. Your replies suggest that I should be doing an Edit Envelopes step before this? The only thing I can see to do is use the Move tool to alter the shape/size of the envelope (?).
Many thanks for your advice, much appreciated.
Bev
10/18/2005 (12:57 pm)
Hi there,thanks for your replies. Even more support for the Skin modifier approach so I really must get this sorted!
Can I backtrack a moment to expand on both your comments about "adjusting envelopes"? i.e pre- Abs Effect adjustment or Step 2 in second mail? Please could you clarify how exactly you go about this?
Perhaps I have been jumping ahead a step? You see once I've applied the skin modifier I'm going straight to 'Edit Envelope' button, checking 'Vertices', selecting an area of vertices and then selecting a bone from list and changing Abs Effect. Your replies suggest that I should be doing an Edit Envelopes step before this? The only thing I can see to do is use the Move tool to alter the shape/size of the envelope (?).
Many thanks for your advice, much appreciated.
Bev
#4
When you select a bone (you can either click the gray envelope in the viewport or select it from the list of bones in the skin modifier) you will see a series of circles and some small boxes.
Simply grab one of those boxes and start moving them around so the envelope matches up as close as possible to the body part you want that bone to influence.
10/18/2005 (1:03 pm)
Yep, you're missing one of the steps. =)When you select a bone (you can either click the gray envelope in the viewport or select it from the list of bones in the skin modifier) you will see a series of circles and some small boxes.
Simply grab one of those boxes and start moving them around so the envelope matches up as close as possible to the body part you want that bone to influence.
#5
I'll give that a go and fingers crossed I'll be a skin over Physique convert!
bev
10/18/2005 (1:14 pm)
Oh big thanks magnus,I'll give that a go and fingers crossed I'll be a skin over Physique convert!
bev
#6
that and paint blend weights for joints..
do envelopes operate differently, or are they just a selection aid with some weight blending built in as i thought?..
i.e is there any real benefit besides personally workflow preference...
10/18/2005 (3:15 pm)
Hmm.. i must be odd cus i dont use envelopes at all.. vertex only for me!..the lasso selection tools a gift here...that and paint blend weights for joints..
do envelopes operate differently, or are they just a selection aid with some weight blending built in as i thought?..
i.e is there any real benefit besides personally workflow preference...
#7
10/18/2005 (3:26 pm)
It's best to think of them as a selection aid. Any verticies that fall within the envelopes near range are selected and given a normalized value of 1.0, verticies that lay between the near and far envelopes are assigned a normalized value that ranges based on how far away the vertex is away from one near envelope to another near envelope.
#8
10/26/2005 (2:26 am)
Thought so.. thank u! 
Torque Owner Magnus Blikstad
Then when it sort of works I go in and adjust vertices that have problems by hand. Either by selecting them and adjusting the "Abs. Effect" or by simply grabbing my wacom tablet and using "Paint Weights". I never use the weight table, it's just too messy and confusing.