Stretch / Pull together folding structure

[1023681]

Hey guys,

I'm quite new to 3dsmax and have some problems modeling/animating an articulated bus. Especially these folding structure around the joints.

I recently modelled this folding structure but I want to use it for animation as well. E.g it should stretch and pull together when driving around bends.

I already tried it with skin modifier but I don't know if it's the correct approach...

I hope you can help me. 

Thanks in advance. 

Best regards.

[RobH2]

Maybe a 'Hose' from 'Extended Primitives' could work. They don't have a lot of controls but it might get you by. They seem to work best in only one axis but if your bus just articulates from side to side and not up and down it might suffice. 

I've attached a video and my test file. See the Max Documentation for more help with it. 

[RobH2]

I was thinking more about this and you might explore using 'Bones' as an alternative. I've attached another video and Max file. This is a starting point and would need a bit of work but the nice thing is the bend works on multiple axis so if the bus goes over a hump, it would work better than the 'Hose.' 

I'm not a character animator and I don't suggest to be very good at bones, but I think it's worth exploring. 

[1023681]

Hello Rob,

this is very helpful. 

I will try it out immediately. Thanks a lot 🙂

[1023681]

How did you get these smooth transition between the bones?

Everytime I try it and look for the envelopes it's all red and not a smooth gradient like yours...

[RobH2]

Bone and Envelopes are a complex endeavor. I'm not expert. You'll need to do some tutorials or get a tutorial on Udemy or something to get all the correct instruction you need. I believe Bones might be your answer though. 

[RobH2]

One suggestion, anything can be a bone. Maybe use thin planes that are the width and height dimensions of your bellows. You'll be able to read the Documentation about how to link them and convert them to bones using the Bones Tools. That approach sometimes presets a good Envelope size.

Otherwise, for real Bones, there are spinners for the 'Fins' of each bone that you can keep playing with until they reach out to the width and height. That's what I did, I played with the Fins until they kind of matched the bellows extremes. It's a lot of back and forth until you get the size and the angles right but eventually you can get something close. Open my file and look at the bones, you'll see what I adjusted. 

[1023681]

I did everything exactly as you said, but I just can't get the envelopes to deform so that it's effectively a flat capsule.
The thickness of the capsule or its radius cannot be individually deformed or scaled.
This is my main problem...

[RobH2]

The radius of the 'FlatCapsule.PNG' looks large. Can you reduce that so it's closer to the size of the real mesh? Does that help?

I'll look at this again and see if I can think of another way. I had hoped someone else would have poked in here and had a suggestion. 

[RobH2]

Did you do any tutorials on Bones and learn deeper about Envelopes and Weights? If you just poked around at it without doing any deep reading it's likely you'll have problems. Bones are kind of complex. 

I've returned another file. This one has just two Dummies that represent the two parts of the bus. I've used the 'Weight Table' to start to assign weights to one of the Dummies and one side of the bellows. The weighs of the verts next to the Dummy are are '1.0', full on. Next to the other end it's '0.0'. In the middle it's '0.5'. But, as I watch it move, I think it needs to taper off faster. Maybe the center of the bellows needs to  be '0.0' and go to '1.0' gradually from there to the Dummy. Then you'll need to do the reverse on the other Dummy. I didn't do that one yet. I figured you could open it and see what I did to Dummy04. 

Dummy04 does distort a little as it rotates. Maybe that dummy should be much shorter and not long like a bus body. You are going to have to play with it but I think if you do enough reading and tweaking, bones and do a nice job for this. 

Here are some helpful links:

Objects as Bones

https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/3DSMa... 

Weight Table

http://docs.autodesk.com/3DSMAX/13/ENU/Autodesk%203ds%20Max%202011%20Help/index.html?url=./files/WSf... 

Weight Tool

https://knowledge.autodesk.com/support/3ds-max/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/3DSMa... 

[CAMedeck]

I had an articulated bus that used Volume Selects with Falloff enabled on the vertices of the accordion.  As I recall, there was a non-renderable box linked to the front and back sections of the bus, and they overlapped the accordion piece by about one fifth of the length on either end.  As one end of the bus turned, the vertices immediately adjacent would move and then the strength of the movement would diminish to the middle of the accordion object.

[RobH2]

@1023681, did you ever solve this to your satisfaction? If not, let me know. I have some info I can send you. 

[1023681]

hey and sorry for the late reply.
Unfortunately I didn't manage to create this articulated bus with the pivoting articulated center part....
In addition, other work came up, which is why this project is delayed until today...
Nevertheless, I am very grateful for further assistance.

[RobH2]

@1023681 

I know it's been awhile. Did you ever solve this? If not, I have some additional info for you.