Moho Forum

I posed this question to the Anime Studio Pros Facebook page and am curious of anyone else may have a solution:

Problem: I would like to have the noodle arm on the left that is using point binding but with a bitmap (.psd) file that is bound to the arm, like a tattoo. The closest I could get was using a smooth joint like the example on the right. I was able to do a smooth joint on both the arm and the .psd file. BUT, what if I wanted both a noodle arm, like the elbow on the left with the tattoo on the right? My result was garbage, right in the middle. You can see that using flexi binding creates a shifting of the .psd layer. It doesn't follow the curvature of the noodle arm as I'd like it to.

Solution: Victor has a great solution but I'm curious if there are any others out there before I post his here.

So, here is the challenge!
Can you create an arm that has a curved elbow (noodle arm) but has a bitmap attached to it in a way that it follows the curvature accurately?

You've thrown down a gauntlet! I fancied giving this a go as I almost never use textures - and now I just might!

I'm looking forward to seeing Victors solution!!

I tried a couple of things first, both a textured stroke and a normal texture, neither had the control needed.
In the end I decided to use masking.



First I draw the tattoo layer over the arm, not masked and slightly overlapping. I rendered that frame on its own and saved a transparent PNG.
I then added that PNG as an image layer masked by the arm - the skin is the vector arm, the tats are on top transparent.

Image deformation is just a case of 'pin' distortion. I figured I'd just need enough points to map the tats to where they should be during the animation - I put one small bone over each 'tat' area and an extra next to the arm crease - this helped keep the bicep tat off the forearm when bent.

I put two bones in to control the arm bend. It's important to make all of the 'pin' points parented to the upper arm (I found out the hard way).

I then created a smart one for the lower arm. as it bent, I moved all the pins to where they should be, rotated them and sometimes scaled them to make the mapping match as close as I could (without spending too much time)... my result isn't perfect, but it's a proof of concept More pin points and more effort in the placement would have given better results. I LOVE SMART BONES. Do the hard work once, and from then on, its the same as animating any arm.

Here is the AS11 file: http://www.mediafire.com/download/s3a79 ... /tat.anime

Here's what I posted in Facebook

That's a fun challenge. I made a fast test. It works well, but is more complex than I'd like.
https://dl.dropboxusercontent.com/u/544 ... _tatoo.zip
The points are bound to the two arm bones. The image is flexi-bound to other bones (which are hidden). When the forearm rotates, that bones correct the tattoo shape (via smart bone).

actually it's less complex than mine, although I think mine gives more specific mapping control over certain areas.
I also thought, to avoid distortion (since the bone weight is providing the influence) to have one bone over each 'tattoo' area you want to keep but have 2-4 child bones around the actual specific tattoo area parented to the main bone - this would keep the shape from distorting, in theory... I will try to update my experiment to see if it works

I think your first one looks good, Danny. Just enough distortion to look like muscle flexing.

thanks

FYI - all bones except the two arm bones are flexibound to the tattoo layer, the arm is flexibound to the arm bones (Control+shift+F)

I've had another thought regarding upper/lower arm separation... you could have two copies of the texture layer, and a reference of the arm layer - one with a fill on top, one on bottom (separate masking), so they could morph as one, but never overlap? might try this later

My other two ideas didn't really pan out -the whole thing just got more complicated.
Here is an update using the exact same rig as the one on my first post - but finessed a little to reduce distortion. The main problem area is around the elbow, and it could maybe benefit from an extra bone in there to maintain the image volume, but I don't think it's too bad in general...

I think you are being too hard on yourself - that is pretty convincing.

I didn't mind hundleyjareds middle attempt either tbh - if you turn the fist a bit during the move it would look the the arm is rotating and wouldn't look like an accident

Nicely done funksmaname! That last one you did is really great, I love how you came up with a good solution and improved upon it. Now we just need a one button solution for this in the next update right Thanks so much for taking on this challenge, I'm going to try out the methods that both you and Victor developed in the future for sure, it really opens up some possibilities.

another thing that might make things easier is not to export the entire arm tattoo as a single layer - if you had different elements, they could all be very accurately controlled independently with a single bone for their position/scale/rotation so you would probably get really clean results... it depends on your design really

Good luck - update this post in future, in case you improve upon or discover an alternative idea... it was an interesting challenge!