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Spinning with keyframes

Started by SickAlice, August 26, 2015, 07:00:15 PM

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SickAlice

It comes back to this. I'm trying to make a piece of a mesh spin in a circle via the keyframes. In the past I've run to some trick, either using an already spinning piece in position on a mesh or using an animated texture trick. In this case I can apply the step animated texture trick (several models at different positions assigned to different texture coordinates, animation controlled via alpha channels) but that won't create the transition I want. So think basically a fan or turbine one the front of another part that turns around but only does so during choice animations and stops turning in others. Obviously the static part isn't a problem, but the rotating part is. I know there's a correlation here to Quarternion keys but all my attempts lead to the piece being thrown about all over the place. So, the question is whats the detailed process to make a piece rotate on it's axis via the keyframes? I searched many threads but it always stops short of " won't go into detail on this ". Today however in detail on this is exactly what I need. Thanks in advance to anyone who reads this and responds.

AfghanAnt

you could always take a fx that spins and put the mesh piece on it to spin.

SickAlice

#2
I've tried this however the ones I came across spun via animated texture rotation. Now that you mention it though I think a spinning axe or the like would probably have to have a conventional rotation to it. If that works I could make two instances of my gear, static and rotating then control them in the keys via the scales. Thanks for the suggestion, I'll try it out tonight. I still do want to know the proper way to set this in keyframes though just for completions and knowhow's sakes. And for any future skoper that may need the information.

* I gave it a go with Spinning Axe but it's not retaining the spin. I'm likely doing something wrong but don't know what.

detourne_me

I think scaling static and rotating pieces would be one way to go.
I haven't had to much luck with quarternion keys in the past. I think maybe it could be done with translation keys, if you added in a few more translation keys, copy and paste all of the coordinates, but slightly change the rotations for each keyframe. (This is the same kind of trick I learned from looking at Windblowns scopes for growing/shrinking arms and stuff.)
The other suggestion would be to take a look at a mesh that does do static and rotating objects, like Texas Jack's Ork_Warbike.

SickAlice

The warbike, I think I have that one. Judge Dredd also has a rotating front tire and scaling for that matter. I never quite understood the process though as many times as I looked at it. All my attempts to futz with the tire led me to the same end as now where the model just flys about all over the place.

detourne_me

Yeah, if you were using the Judge Dredd then i can see how the scaling and rotation would throw it out of whack on a normal mesh,   the wheel is constantly to scale on the warbike though. that might help.

yell0w_lantern

What are you trying to make, exactly?
Yellow Lantern smash!

SickAlice

It's for the Technodrome, for the spinning fork on the front of it. Or more accurately the fork I want to spin though I've wanted to learn this for awhile for some other ideas.

yell0w_lantern

Obviously you want rotational keys but they may have a different name in the program you are using.  I find that it is best to use a free piece of geometry (no shared vertices) with the non-rotating part of the mesh (again, pretty obvious) and physique it to a relatively free-moving bone like the head, wrist, ponytail, or a new one that is just attached to the other bones.  I think you can assign controls and constraints to make sure an added bone only moves certain ways but I have never worked with those.  Now another fairly obvious bit, never rotate very far between keys or it will look like you are going backwards.

Finally, something less obvious: the axes have to be aligned to your mesh piece NOT aligned to the world axes.  If you align your axes to anything but the piece of geometry you want to spin you will get weird results. depending on how you want it to move you might center the axes in the piece or on one end.  So alignment and placement are essential.  In Max this is called the Transform Gizmo.

As an example, a transform gizmo centered between the feet of a human figure in the ground plane could be scaled to make a bigger or smaller human still on the ground plane.  Alternately, centering the gizmo inside the figure and scaling would make a large figure sticking down through the ground plane or a small figure floating above the ground plane.  Conversely, rotating the first example would rotate it around the ground plane possibly even to the opposite side whereas rotating the figure with the axis centered in the mesh would spin it but it would stay above the ground plane.

If pieces are flying around then the pivot point (Transform Gizmo) is not set correct for what you are trying to do or, possibly, there is another bone influencing the one you are trying to move.  I suppose there may be other possibilities but these seem most likely.
Yellow Lantern smash!

SickAlice

It's a starting point though I'm more specifically looking for the 1 to 10 in Nifskope. Like most the exact version of Max isn't available to me so I have to make do with else. Nifskope operates a bit differently than your describing and is pretty touchy when it comes to the exact settings of a thing. In most cases a flaw is caused by just having the wrong value in one area or wrong type chosen and so on. So I'm at a point of trying to narrow that down instead of shooting in the dark. I should probably just crack open the Netimmerse manual really. I'll get to that exactly tonight actually, brushing up on it is always a good thing to do. Your on something about coordinates. I thought about that but didn't approach it, yet. I can't recall the right terms either as I had a long day and somewhat traumatic incident, but in keyframes there's XYZ values. In the nif there's XYZ as well and by each piece. Likely I need to copy over those values from the fork to the keyframes in order to let the animations know where the center is at. The fact that I haven't may be accounting for why the piece is jumping about and as you said, following the world values. I'll test that probably by tomorrow night, to much on the agenda tonight instead. Also I should probably eat one of these days, starved are the driven, lol. Oh and the geometry is free so we're square there.

yell0w_lantern

If you can't get it, send me your geometry and a rough idea of what animations are needed and when you want the fork to spin.  I can do some Max work for you.
Yellow Lantern smash!

SickAlice

Thanks for the offer. Again like I said I want to learn how to do this in Nifskope though mostly because I plan to do something similar a few more times. I know it's really just a matter of opening the keyframes and entering the right values, my question is which and what's the equation to determine it by the piece. I'm really not interested in being educated in Max as I have version 9 only and it isn't applicable to me.