Moho Forum

I'm working on an animation clip that features a ceiling fan spinning. I have no real idea
how to go about creating this effect. Anyone here know how I should approach this.
Maybe you have animated something else that could work to create a spinning ceiling
fan effect. Of course it's the blades that I would need to spin. Any help I could get would
be greatly appreciated.
pkscomix

Easier to whip something up and show rather than tell: http://www.filedropper.com/ceilingfan
I used 3D vectors, angled each fan blade, and angled and rotated the group.

I recently posted a ceiling fan on Show Your Work.

You can Import a video of an actual ceiling fan and trace it, frame by frame. You can create it in Moho with the 3D tools. And you can "wing-it" with point animation. What you do depends on your style.

The main thing to remember is that one generally animates the blades rotating from START to ONE-FOURTH of a circle, then you employ "cycle" on the keyframes to repeat the animation. It will look like the blades are moving in a full circle, but actually they are only moving 90 degrees, over and over.

Oh, one more idea. Make the blades a transparent ellipse, so that it looks like they are spinning fast. Maybe animate a slight wobble to the ellipse.

It's no harder to just animate a full 360˚ cycle.

I did a test animation of a helicopter where I used perspective *Rotate Layer XY tool. I rotate it in the x like 90 degrees and moving in the time line rotate the y as many as you need (or 360 and cycle) Back in frame 0 use the Transform layer tool to move it up so you can actually see the blades. Hope that's what your looking for.

Also if you use cycle make sure your key frame is set to Linear. And it wouldn't hurt to line up your origin point with the layer and use shift to constrain the movement.

I've been following this thread with curiosity, and wondered what would happen with a more complete ceiling fan. So I made a version of the spinning ceiling fan blades pretty easily, but when I inserted the center hub (a shaded circle facing camera,) I had trouble getting Moho to sort the layers properly.

Here's the problem: I can get the center hub to render behind the blades or in front but not within the blades where it should be.



Before starting this project, I assumed that enabling Sort Layers By True Depth and/or enabling Sort By True Distance for all the groups should take care of this but it doesn't seem to affect this setup. Maybe if all the layers were inside a single group? That might work but it could also makes it more complicated to animate the fan blades.

I don't really want to spend too much time on this exercise, so I'm wondering if anybody knows of a solution. (I mean besides setting this up in an dedicated 3D program. I know how to do that.)

Stuff like this makes me wish Moho had null items that I can parent things to and animate. Not sure that would solve this problem but nulls do make creating and animating mechanical setups much easier. (i.e., especially for camera rigs.)

Anyway, it's no biggie, I'm just wondering if this was possible in Moho.

Follow up: Yeah, the sorting works fine when all the blade layers and the hub layer are in the same group. But now animating it becomes more complicated. I guess I can spin the group and set the hub layer to Face Camera. Not ideal but it might work. BRB.

Edit #1: The group already had spinning animation so I kept that and enabled Face To Camera for the circular hub drawing. I tried all the Face options but I didn't get the result I was looking for.

Next I tried applying some of the 3D effects on the circle. I can see how this might work but none of the options made the circle into decent sphere. I guess if we get 3D support back, I could just import a real 3D sphere. But, in this case, I would rather use a 2D image for the hub.

Anyway, it's only academic. If I had to do this for real right now, I'd just set this up in a 3D program and comp it with the Moho render.

Yeah, in the same group, and you have to lathe a half-circle to get a good sphere.

Oh, wait...we still have OBJ import, so I can import a sphere. Never mind.

Still would like to figure this out with a 2D hub though. Not necessarily for this fan setup but as a general technique, it should be possible.

Importing an OBJ sphere and removing shading solved this case. If I leave shading on, the facets are visible. Not really what I want but it's one solution.

For the 2D hub, I guess I could use animated layer order. It would work but it would be a silly way to do this.

Just put the hub in a group, XY rotated the same as the blades group, and counter-rotate its cycle.

Here's another variation. It works...sort of...



Here's the project file...

fan.moho

Basically, I animated a single fan blade, duplicated it three times, and then offset the keyframes in the Graph Editor. (Sequencer offset would work too.) Since all of the layers are separate, they rotate freely around the 2D circle layer in the middle.

I wonder if the blades could be bound to a single bone and spun around. That could simplify the animation.

But I think my curiosity has been satisfied so moving on.

I couldn't resist: Here's one using a single bone for the fan animation. The result looks exactly like the above but the technique is much simpler. Here's the project file...

fan_02.moho

Here's what I changed from the first version:

1. I killed all of the animation keyframes for the four Blades layers.

2. Next, I converted the Blades group to a Bone group, and created a single bone at the center.

3. I selected all four Blade layers and used Layer Bind to bind them to the bone.

4. Since I do not want the bone to affect the hub artwork, I set the bone strength to 0.

5. Finally, I animated the bone, rotating it 360 degrees and setting the last keyframe to Cycle.

This is much simpler because I only needed to animate one item instead of four. If I were to take this one step further, I'd setup an SBD to control the fan speed.

Ok, now I can move on.