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Hellishly Over-Complicated Robot Seeks Rigger for Quiet Nights In

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#1 iline

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Posted 08 August 2012 - 09:53 AM

Hiya,

Still trying to finish this f**king robot model. Anyone fancy taking a look at these robot's legs and telling me why I can't mirror it properly - and what the hey I could do better. I know learning on the job is better than watching video tutorials, but I'm bang outta time and making an enemy of Euler.

Please, O community of Cactus Dan acolytes, spare me from the onslaught and 'ave a butchers at this over complex TurboSquid-3DS-to-C4D-converted hulk of a robot.

Oh, and yesterday. For free. (jokes)

Merci, au revoir, mes bon vivants...

http://www.sendspace.com/file/ghdata

#2 brake

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Posted 08 August 2012 - 02:42 PM

Took a look see. I don't have the CD plugins though. Did some googling and I can't see any advantages of a CD aim constraint over a standard C4D one?

#3 iline

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Posted 08 August 2012 - 06:09 PM

I think they just tend to benefit the workflow of someone using the IK and character tools Dan's made, but there is an field to specify an Up Vector in the constraints and for the alignment axis to be specified, which doesn't happen in the native tags. If I knew more I could have stuck with the standard tools, but I thought that buying the CD kit might actually benefit me as a noob rigger. But actually, I'm in over my head.

The CD Constraints are free to download and pop in your plugins directory, but if you don't buy it, you cannot edit the properties of the CD tags.

Thanks for your interest, brake...

#4 iline

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Posted 08 August 2012 - 06:11 PM

This may well turn into a job posting as we're a week behind now, PM me if you're a rigger looking for a challenge and I'll send you the whole robot to get an estimate of time.

Indecision becomes decision, with time...

#5 oeuf

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Posted 09 August 2012 - 03:06 AM

You should email the man himself, Cactus Dan. A friend of mine recently bought his tools and needed a little help and CD was Johnny on the spot!
I thought it was pretty cool of him. Give it a try.

#6 iline

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Posted 09 August 2012 - 08:45 PM

oeuf - He's busy but I'm glad he is, because I have fixed it! If i'd got someone else to help I wouldn't have had one of Oprah's a-ha moments and got my head around some of the core (and VERY poorly documented) aspects of rigging...so it's shaping up nicely now. It took staying up late a couple nights but now I'm one of the best C4D guys in London. Fact.

#7 iline

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Posted 09 August 2012 - 08:45 PM

And one of the most modest too.

#8 vozzz

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Posted 09 August 2012 - 11:01 PM

Lolarama :D

-Aleksey

 

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#9 oeuf

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Posted 10 August 2012 - 01:30 AM

So what was your solution?
Nice looking robot, couldn't do anything with it though as I don't have the CD's Character tools.

#10 iline

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Posted 10 August 2012 - 11:51 AM

OK, sheesh, I had a little help from a friend... London C4D freelancers = sucky

#11 iline

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Posted 10 August 2012 - 12:15 PM

The solution, which helped everything, was that I took a long look at the core hierarchy of the leg's bones. This was a model imported as FBX which had lost its bones and constraints, but helpfully all the parts were numbered sequentially so that I could work out where the joints where placed and to which IK goals they were looking at. There were no pole vectors at all, but as I don't know how 3DS max works, I didn't know if the modeller had used 3D IK solver or normal 2D.

There are three main bones, to which the geometry and additional articulation bones are attached. There is no deformation of geometry at all, everything is metal, so therefore you just nest the mesh objects underneath the bones that relate to them and they inherit the bone's rotations. The foot is separate as parented to the IK goal of the leg joints.

So I dived into these main leg bones, made the top joint exactly along X from the hip joint, and hit the Joint Align tool on that main hierarchy. The Align tool is NOT the same as the Joint Align tool, I figured out.

To mirror the geometry correctly, and this seems very important, I deactivated IK and Constraints for all objects within the character menu. With no external forces acting upon the duplicate geometry, the Mirror was precise. When I turned IK back on, it did not deform back to the shonky way it did when I mirrored with IK on. Success, but a minor one.

Where constraints were misbehaving, I made sure to manually zero out the twisted geometry (in Axis mode in the Co-ordinate manager, then hit Apply. Reset PSR does all three...I'll make a Reset R button one of these days). I started to notice that some of the double targeted pistons were now behaving correctly. If someone can explain the evaluation order (Initial, Expressions, Generators, -499-499 et cetera) then maybe I can get rid of the lag or at least put them somewhere in the hierarchy where they are evaluated at the right moment. I can't work that out, so the most important double-targeted pistons are still misaligned)

Once I started to lift the problematic parts out of their nested hierarchies and place them using Parent constraints, the evaluation took place in the right order and there was no longer the same lag that occured in animation.

I am still getting issues with circular dependency, like the double targeting on pistons for example, but I will just Ctrl+CNV those into new scenes, fix them in world co-ordinates and then try to float them above/below the main leg hierarchy using Parent constraints to pin them to the correct nulls.

I even got a great tip from Vozzz here about constraining an object to the Bounds of another object using a Clamp constraint. If that other object is a Spline Primitive, then you have a cool way of making a planar constraint that you can see, squash and stretch with xpresso, and mostly importantly, that has that really useful flower shape that everyone always uses (why still there in r13, I wonder?)

Next step is tightening up the rig and starting to hone the animation, which is more an art than a tech challenge, but then I'm advertising Skrillex, so it's not got to be ballet, or anything.

I should be blogging this, right?

#12 oeuf

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Posted 10 August 2012 - 04:26 PM

Ha, you should be blogging it. Thanks for typing it out.

#13 vozzz

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Posted 10 August 2012 - 04:30 PM

do not use the parent constraint, it is buggy as hell. use PSR with a nested Null.

-Aleksey

 

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#14 iline

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Posted 16 August 2012 - 11:31 PM

Erm, what? Parent never seemed to work (the Cactus Dan one does, but with the same evaluation lag) but I what do you mean to use a nested null? As in, PSR tag a null to target another, and nest the geometry under it?




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