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How to use IK for a guitar strap
Posted: 22 October 2012 09:23 PM   [ Ignore ]
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  I posted about this problem before but I have a different take on it.  I have also included an image to illustrate better.  I have seen other examples done on figures that make me think that IK would work for this but I don’t know how to do it.  Everybody knows how guitar straps work.  I’m not trying to make a virtual guitar strap but one that I can animate easier than it is right now.  It takes a long time to shape this thing the way it is set up, now.

  I purchased this guitar/strap combo.  http://www.renderosity.com/mod/bcs/rock-school-lp-guitar/94912
Sorry couldn’t find one on DAZ.

  The strap is boned and has 25 segments. it has controls which work when you get the hang of it but I think it could be better.  (See image) I turned off the figure so you could see what I mean but believe me it is there and fits perfectly.

    Like I was saying,  I think it could be boned from the back of the strap going out and use IK so that you could move the ends in a way that they would move but not moving the middle.  All I need is just a little bit of movement up/down, and side by side.  Even if I can’t pin it to the end of the guitar, being able to just moving the two ends without the back strap moving would be so much easier.
Any ideas?
Thank You
Steve..

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Guitar+Strap02.jpg
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Posted: 22 October 2012 10:19 PM   [ Ignore ]   [ # 1 ]
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It would be easier to create the Strap, create some morphs (up, down, stretch, movement- moving the ends, not the back) for the strap and import them. Then parent the guitar to the strap, create a Null and parent the Strap to the Null, then parent the Null to the character(chest or whatever). Using a null gives you some extra rotation and travel options, without being seen. However, this Idea would be for your own animations, might take some special scripting magic to make it a functional, sellable product.

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Posted: 22 October 2012 10:48 PM   [ Ignore ]   [ # 2 ]
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    That’s really interesting. I see what your getting at. I have limited experience with this.  Yes it does sound just a little more limiting, than I had hoped though, because I don’t know if I can plan that far ahead. Remember, I am also going to have to animate the hands, too.  I might very well have to go that route but I’m not going to give up on the IK idea just yet.

  I’m also trying to bypass getting into modeling, until I absolutely have to.  It’s a whole other program I’d have to learn.  If I could stay in DS and Photoshop, I’d be a happy camper.  I’m looking into a few tutorials about IK and rigging.  I’m thinking there’s got to be a way to do it this way. I’ll keep it in mind though.

  By the way I’m not at all interested in selling it.  I’m just into the animations.

Thank You very much
Steve

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Posted: 23 October 2012 12:18 AM   [ Ignore ]   [ # 3 ]
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You might consider Easy Pose as an alternative.

A couple of warnings:

Easy Pose is an old poser technology. I’m pretty sure it worked in DS 3 but I’m nor sure about 4, let alone 4.5.
Some of the products I’m going to mention are on an X rated site and in fact they were released as bondage items.

Here are some Easy Pose freebies that you can DL to see how the technology works.
http://www.renderosity.com/mod/freestuff/search.php?section_id=-1&query=easy+pose+&sort=relevancy&use_age=no&older;_age=&older_units=day&newer;_age=&newer_units=day&username;=

Here is the Easy Pose tube which is the most generic and versatile of the items. If you flatten it, you may be able to use it directly.
http://www.renderosity.com/mod/freestuff/details.php?item_id=6590
http://www.renderosity.com/mod/freestuff/details.php?item_id=19756

“Easypose underground” will allow you to create a model and add Easypose to it.
http://www.runtimedna.com/Software/?page=3

Lastly, over on renderotica, there is a product called “Tight Kit 2” that has straps that could be used right out of the box. As I said, this is a BDSM set, but it a VERY versatile item and could be used for any number of uses similar to yours. (Strap up a suitcase, rubber band holding things together, A harness for any fantasy creature that you have the time & patience to fit, etc)

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Posted: 23 October 2012 04:45 PM   [ Ignore ]   [ # 4 ]
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Put some more Nulls close to the guitar, then in the Genesis Parameters tab in Misc ... Point the hands at the Nulls and and in the Scene tab parent the nulls to the Guitar ....
..
the only problem with doing it this way, is you have to keyframe it on the timeline, especially if you move the Nulls. You can’t save it as a pose or use the Puppeteer. When bodyparts are “pointed”, their position is not saved, so you have to Keyframe the Null ..... So it will work for Your animations, but it would be difficult to try and package all this as a Product at Daz ro Renderosity ....
..
Try this. Take a new scene with a stock Genesis. Create a Camera looking at Genesis, Point the eyes of Genesis at the camera, point the Camera at the Neck or chest. Then create a Null directly above Genesis head and point the head at the Null. Then parent the Null to the camera .. now switch the view to the Camera and move around. To make or keep an animation this way ... you need to keyframe the Camera .. that will move every thing else .... You can set up a whole scene like a Mousetrap, this moving that, that moving something else, then add a few morphs for realism .. hair and clothing movement. Just remember to keyframe the original parents that move, and everything that morphs, and also switch to the Perspective View to edit when using a Keyframed Camera ......

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Posted: 23 October 2012 05:17 PM   [ Ignore ]   [ # 5 ]
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Also, make use of the Memorize/Restore Pose options .... say you wanna make a pole dancer. She does a couple poses then jumps up on the pole to spin. Stop at the Pole pose and render those frames. Then memorize the pose, clear the animation, then restore the pose on the first frame. Then parent the dancer to the pole .. and Spin the pole for the next animation ..... Render those frames. Stop on the end frame (should be turned a different direction) Memorize, clear, restore… then go from the pole to a pose .. render ... put it all together with VirltualDub ..... or whatever

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Posted: 23 October 2012 09:14 PM   [ Ignore ]   [ # 6 ]
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JustmeNthere,

I’m not sure what this has to do with a guitar strap I want to re-bone or re-parent.  Funny as it may seem, I am having no problems animating the hands playing the guitar, if that’s what you’re getting at.  It sounds like what you are describing is a little above my experience level.  I have to study your techniques as described to figure out what you are animating.  And I have no idea what you doing with the pole dancer thing, either. I’m sure it’s me.  Thanks for the try though.
Steve

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Posted: 23 October 2012 09:28 PM   [ Ignore ]   [ # 7 ]
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To pwiecek,

  This stuff looks interesting. I noticed the Easy Pose software itself is PC only.  I’m on mac, although I see that some of the props are for both platforms, especially the tube, which looks very interesting. From the description it sounds like it works exactly like the guitar strap I have.  I haven’t tried it yet but I will.  Also I looked at the rope and the chain but they say they are stand alone. Not sure how to get that into DAZ Studio, though.  They look very usable though.

  I think what I have to do is to re-bone or re-parent the bones in the strap.  I really believe this will work but I haven’t learned how to accomplish it yet.  I have been reading a lot about rigging. Something I really didn’t want to get into, at this point but that’s what I’m doing.

Thank you
Steve

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Posted: 24 October 2012 01:11 AM   [ Ignore ]   [ # 8 ]
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Some of the posts after mine make it seem as if you are looking for animation. Unfortunately, I don’t know how well this stuff will respond when animated.

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Posted: 24 October 2012 09:05 AM   [ Ignore ]   [ # 9 ]
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From what I understood, you want to use a Strap you made, with a guitar from someone else ? If it were me, I’d export the guitar as a (.obj), export a stock Genesis at SubD-0 as (.obj) then import them both to Blender or Wings3D, make my strap, then export the guitar and strap as a single (.obj) ... then move the guitar, adjust the strap, and export again .. for a morph target .... then move the guitar .. adjust the strap.. ,and export again as another morph target. I’ve found I can use all the old Poser hair/clothing/ this way, manually fitting it, exporting a morph, then using the Morph and the “Current” setting in Transfer tool. ..

... You’re Idea with IK is right, and should work ... but your Hip or Root would need to be the center of the strap. You could make one long bone for the guitar, point it at a null .. and parent the null to the other end of the strap .... but it would be easier to just use Morphs .....
You have a lot more control in Blender or Wings3d or Hexagon (I’ve never used it) .. to get the look and feel you want. To make a strap look natural with Bones ... you’d need a lot of bones, and then with IK ... you’d have to do a lot of key-frame editing still to make it look right

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