Timeline - changing frame 0 pose alters later keyframes?

mikethe3dguy

I'm trying to set up a simple animation to facilitate dforce simulation of clothes and hair. I posed the figure at frame 0 as I wanted it to end up, then expanded the timeline to 51 frames. I made a couple alterations to figure position at a couple points along the timeline (frame 25 & frame 30). At all the later keyframes (25, 30 and 50) I had selected all figure parts and children before saving the keyframes.

The problem arises when I try to, at frame 0, set the figure to the default A pose. Once I did that, I checked frame 25 to make sure all was well, and was surprised to see that the figure was now also in the A pose at frames 25, 30 and beyond. This is confusing. Aren't the keyframes I added supposed to prevent this?

How do I do what I need to do?

DrunkMonkeyProductions

What happened is what's supposed to happen.

Each keyframe is based on the previous keyframe.

that is, Frame 15 is based on the information from key 0, 30 on 15, and 50 on 30. Assuming only 4 key frames.

Delete, or change, 0, or any frames in between, and all subsequent frames change, 15, 30 and 50 in this case.

Generally for d-force sims, you want the pose to be at 15 or so, and any alterations between 15 and 30 with the final at 50.

Although, that's what most of us are told, and it's a bit of hogwash.

While the results might be better with that layout, you can get away with fewer keyframes and in some cases just pose the character at frame 0 and get the same results, albeit faster, than with 50 frames.

Mostly depends on the product used, the pose, and whether using wind nodes and other assets or not.

 

mikethe3dguy

Okay thank you, that helps. I had thought keyframes were fixed and locked when saved, and only the frames in between dependent on keyframes before and after. But is there any way to solve my problem - any way to for example lock the figure's pose at frame 25 so I can alter a keyframe before it without affecting 25?

I suppose I could save my character poses from the "completed" later frames as pose presets, then clear all animation, starting from frame 0, and restoring those poses from the presets. Is that the best way?

mikethe3dguy

Well that's what I did anyway. Works fine.

Richard Haseltine

Keyframes are fixed, I think what DrunkMonkeyProductions means is that the frames that are not keyed are determined by the preceeding and often following key frames, and the interplation method used. By default DS uses smooth interpolation, so a chnage to a later keyframe can have a knock-on effect not just to the behviour between the immediately adjacent keys but even before/after them. https://en.m.wikipedia.org/wiki/Kochanek–Bartels_spline