Using PNGs for difficult in-betweens

[Hoptoad]

I've never used PNGs for difficult in-betweens, but it looks like I'll be doing so in the near future. My 6-legged character has 2 bone rigs: 1 facing forward (Pose A), and 1 facing profile (Pose B). The translation of the legs and body shapes and so forth from Pose A to Pose B would be a nightmare, so I decided I should try the PNG solution.

This is my plan:

1. Export the previews of the character in Poses A and B into my drawing program.

2. In my drawing program, draw an in-between of the character midway between pose A and pose B.

3. Import the PNG into Moho.

4. Use layer visibility to show the PNG for a few frames whenever the character turns ninety degrees.


I intend the transition to be fairly fast. Basically, I'm only trying to remove the abrupt, undesirable impact of seeing a character flip instantly from one extreme pose to another.

Any tips?

I need the strokes of the Moho rigs and the outlines in the PNGs to appear similar, of course. Do you use blurring or smears on the PNGs? I suspect I need more than 1 in-between. . .or do I? How many do you use?

Thanks.

[hayasidist]

what I've done in similar circumstances

e.g. this trivial example is a vector man to vector bird: https://youtu.be/ZkOLibHlTpo

"normal" vector / bone stuff up as far as it can go then:
bake that vector to create a new vector layer which becomes the "zeroth" frame of an FBF sequence (using Moho's fbf) [video at about 12 seconds]
make the transition in fbf up to the starting frame of the target rig [video for about 1 second -- best to step though it because the transition is quick!]
let the target rig take over....

e.g.
switch
> man rig
> fbf sequence
> bird rig

The bake vector script is discussed here: https://www.lostmarble.com/forum/viewto ... 32#p173732 - be aware that it was deigned for moho 12, and I haven't updated it since -- it has been used in 13.5, but if you hit a problem using it, let me know.

sadly, the kelleytown links are dead.

[slowtiger]

I see no flaw in your thinking.

I did the same on many occasions, but with more than one PNG. So it's rig 1 - switch layer - rig 2. No motion blur for me, usually. Getting the same line qualty is easy, I render 1 frame from Moho and import it to TVPaint.

[Hoptoad]

bake that vector to create a new vector layer which becomes the "zeroth" frame of an FBF sequence...

The process of creating the new frames in that way might be too time-consuming for the rotation of this particular character, but it should work well with a different, simpler character later. Thanks for the idea.

I see no flaw in your thinking.

I did the same on many occasions, but with more than one PNG. So it's rig 1 - switch layer - rig 2. No motion blur for me, usually. Getting the same line qualty is easy, I render 1 frame from Moho and import it to TVPaint.

I remember you mentioning that you had done this, which is what gave me the idea. I'm glad to learn that my planned process was correct. Thanks for verifying it.

Oh, and thanks for mentioning a switch layer. I'm now thinking 1 PNG would probably be insufficient. I'll probably make 3 PNGs and put them in a switch group.

[Greenlaw]

I sometimes use FBF animation to smooth out transitions between rig poses that can't be resolved with the rig alone. You can see an example of this here (scrub to 0:017 or so)...

My 2018 Demo Reel

I used FBF for the first 5 or 6 frames as Po somersaults into frame. In this scene I used Moho's FBF tools to do this but I've used PNG sequences created using FBF tools in other programs (Adobe Animate, Toon Boom Harmony,) and imported to Moho the same way.

When Po starts to leap, I switch to the rigged puppet version of Po, so the leap, twist, landing, and everything from there forward is the rig. The cape is using two bone chains with some point animation on top using the Magnet tool...so the somersault really is the only FBF bit. Because the same Moho Styles are used for the FBF and rigged puppet, the switch occurs seamlessly. This is one benefit to doing this in Moho instead of in another FBF program; it's harder to keep the looks consistent when you're creating the FBF in another program. (The downside is that I think FBF is still easier to draw in a dedicated FBF program. Hopefully, a future version of Moho will address this.)

Amway, when I'm using an external FBF program for the transition part, my workflow is...

1. First animate the Moho parts, and render out a JPEG sequence. I use JPEG because 1.) it's only reference footage and doesn't need to be high quality, and 2.) a JPEG sequence streams faster than a PNG sequence, and it's more frame-accurate than a compressed video imported to an animation program.

2. Import the reference footage to the FBF animation program, and animate the 'missing' bits. Hide the reference and render out the FBF bit and a PNG image sequence. This time we're using PNG because we need it to be final quality and we probably want it to have an embedded alpha channel.

3. Import the 'missing' FBF bit to Moho and adjust the Moho and FBF animation as needed to make them hook up smoothly.

I do this because Moho is usually my primary 2D character animation program. If the FBF program was my primary animation program, I would probably render a PNG sequence with alpha from Moho, import that to FBF and export my final frames from that program instead.

I like to finish everything in a compositing program (Ae, Fusion Studio, or Nuke,) but that's probably optional for most users.