Why do bones make imported body parts (images, not vectors) distort?

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Kasia
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Why do bones make imported body parts (images, not vectors) distort?

Post by Kasia »

Very new to Moho!

I have imported some image layers into the software, with a view to making a character template.

Quite happy with how it’s all looking - and with how the bones are making the different parts of my character’s body move.

However, I have run into a slight problem.

When I move the bones, they appear to distort. I move my guy’s arm 180 degrees, and his arm changes shape slightly. The change almost feels logical - as if there is something in the software that is accounting / compensating for the movement in a 3D or gravitational way. I am not quite sure how to describe it.

Does anyone know what this or can anyone point me to the relevant default / setting?

It would be much appreciated.
Kasia.
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slowtiger
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by slowtiger »

That's flexible binding, which is on by default. If you don't want this, you need to use Layer binding with your images.
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Kasia
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Kasia »

Thanks, Slowtiger, however there is no option to layer bind or for that matter there's no choice to flexi or point bind. Could it be because I am adding bones to image as opposed to vector layers?
Kasia
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Víctor Paredes
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Víctor Paredes »

It sounds like a flexi-binding and bone strenght issue. Can you share your file or at least a screenshot of your file to take a look?
In the meanwhile, maybe try this tutorial:
https://blog.smithmicro.com/4-steps-to- ... ys-in-moho
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Greenlaw
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Greenlaw »

Kasia wrote: Thu Apr 16, 2020 8:28 am ...there is no option to layer bind or for that matter there's no choice to flexi or point bind. Could it be because I am adding bones to image as opposed to vector layers?
Point Binding is available for Vertex layers only...but you can triangulate the Vertex layer and apply it as a Smart Warp layer to deform an Image layer. This way, you are indirectly using Point Binding with the Image layer. I suggest reading up on Triangulate 2D Mesh and Smart Warp.

Flexi-Binding is the default binding mode. Depending on how you structured your character, you also have the option to use Use Selected Bones For Flexi-binding, which lets you limit the deformation to specific bones. This is nice when you want smooth deformations with certain bones but don't want the artwork affected by other bones. This works with Vertex or Image layers. You can still use Point Binding for selected points along with Flexi-binding but you need to use Smart Warp to use Point Binding on an image layer.

Layer Binding should be available for Vector or Image layers (or Group layers for that matter.) This is a rigid binding method and is suitable for items you don't want deformed by any bones. Note that if you apply it to a group, you've effectively bound every child layer inside that group to a single bone, so make sure this is what you actually want to happen. (For example, you probably don't want to use this with a Head group when you also want to bind face parts to other bones. You could, however, bind all the face parts using Layer Binding.)

There are many ways to approach this and the best method depends on your character design and how you wish to animate it.

Hope this helps.
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Kasia
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Kasia »

Thanks Greenlaw, I appreciate your answer as I have read many of your helpful posts before I signed up to be in this forum. I know about smart warp and I have been experimenting with it, sometimes it just gets so complex I thought I'd try the bones. When you said Vertex layers, did you mean vector layers? Next thing I'm trying is adding bones to each image layer for a separate body part as a separate bone group, I think this should prevent any distortion of the images.
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Kasia
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Kasia »

Thank you so much Victor for the link to the tutorial, I have been looking for something like this! It finally works like I wanted it to :D
-Kasia
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Víctor Paredes »

Kasia wrote: Fri Apr 17, 2020 10:44 am Thank you so much Victor for the link to the tutorial, I have been looking for something like this! It finally works like I wanted it to :D
Nice, I'm happy it helped :)
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Greenlaw »

Kasia wrote: Fri Apr 17, 2020 8:30 am When you said Vertex layers, did you mean vector layers?
Sorry, yes, vector layers. I use too many different programs and sometimes get my terminology mixed up. :)

A custom 'Smart Warp' mesh isn't always necessary because when you apply bones to an image, Moho is actually creating a mesh for you invisibly. If this result is exactly what you need, you should go with it.

The time to create a custom mesh for Smart Warp is:

1. When Moho's auto-generated mesh isn't refined or specific enough to do what you want. For example, if you see faceting after rigging a long thin tail using only bones, you can reduce the faceting by creating a mesh with more segments.

2. When you want to deform the image layer using point binding. Naturally, an image layer doesn't have points but you can effectively give it points by assigning a Smart Warp mesh layer.

3. When you want to also add point animation on top of the bones deformations. For example, if the bones-only deformation looks bad at certain angles, you can add point animation corrections in the Smart Bone Action.

4. When you want to punch holes in the mesh. You typically see this in image-based face animations where holes are cut out for the eyes and mouth.

So, yeah, Smart Warp may seem complicated but it opens a whole new level of tricks to animate with.

And to be honest, it's really not difficult work with Smart Warp. Basically, you plot your points in a vector layer over the image layer, where you want your 'handles' to deform the image. Just think of each point in the vector layer as a small bone with a radial fall-off. When you're done with the vector layer, apply Triangulate 2D Mesh. This command triples the polygons in the vector layer which is necessary for a Smart Warp to work. Then all you need to do is choose this mesh layer in the Image layer's Layer Settings under Smart Warp Layer.

Here are some tips for using Smart Warp:

- When using a custom mesh, don't bind the image layer to bones. After applying the Smart Warp, just leave the image layer alone. Remember the mesh layer is already being deformed by bones, and the image layer is being deformed by the mesh layer.

- When creating a custom mesh, you don't need to create only enclosed shapes. Some users will create enclosed shapes for the major areas and just draw open lines where they want a nice flow of polygons for optimal deformation. When you use Triangulate 2D Mesh, it will create proper shapes based on the vertices you plotted, not the shapes.

- Did you know you can create and edit a triangulated 2D mesh manually. Moho basically sees any vector layer containing vector shapes with 3 vertices as a Mesh layer even. This can be helpful when you need something simple but very specific. (Probably a rare situation. I'm mentioning this mainly so you don't get confused when you discover a Mesh layer you didn't think you created.)

- The image layer gets rendered only where there is a filled filled in the mesh layer. This means you can 'mask' the image by knocking out filled shapes, as described above for eye and mouth holes. This is also useful around the edges. Combine this with a PNG image's alpha channel to get both nice deformations and smooth (non-faceted) edges.

- Smart Warp meshes do not have curved edges. To make an edge 'smooth', you'll need to increase the level of detail in your mesh. (And/or combine it with the transparent edge in the PNG image as described above.)

- The mesh layer should be hidden (click off the eyeball icon.) The image layer will still render because it's using the mesh layer for deformation, not its visibility. (Well, that's not exactly true because it's using the mesh's filled shapes as masks...but try not to think about that too much.) :)

- You can't use the Cropping tool on the image layers when using Smart Warp layers. It just doesn't work. Try it and see what happens. But of course, you don't need the Cropping tool because the mesh layer will 'crop' your image, so if you have Cropping enabled on the image layer before you apply the Smart Warp, disable it.

I can probably think of more tips but that should be plenty to get you started. :)

Hope this helps.
Last edited by Greenlaw on Sat Apr 18, 2020 9:16 pm, edited 1 time in total.
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Kasia
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Re: Why do bones make imported body parts (images, not vectors) distort?

Post by Kasia »

Thanks Greenlaw, you're a trove of great tips. I am learning a lot from this forum :D
-Kasia
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