Cineversity

I’m doing a medical animation, using a purchased, rigged and textured model (human-male) that involves a metal probe entering an incision (roughly 1cm), passing under the skin and exiting through a second incision (pulling a catheter tube through).

I’m assuming I’ll use a pose morph/morph deformer to show the probe passing under the skin but I’m not sure how to go about creating the incisions without messing up the existing uv/texture.

So a line would be seen where the incision is and then the incision needs to open and raise up showing some skin thickness as the probe enters. Any thoughts on how to create those incisions without messing up what’s already there would be greatly appreciated.

Thank you.

Hi Sapphire9,

Please have a look at these two files.
https://www.amazon.com/clouddrive/share/Lu38bJ91JOM1PFcvGJObOslrfGc7VY0vlKBD59ijEMB
(CV3_S24_drs_21_ANic_01.zip)
(CV3_S24_drs_21_ANpm_01.zip)

One covers the idea of the cut. The other one showcase the options to elevate the skin while having an extra Pose Morph that handles only a UV Morph if that is a concern.

If you create a Polygon selection for the new Polygons, you can place them over the existent UVs. With two materials, you have the option to leave the original as is and have a new material just for the Cut-surface. I made a copy during the capturing, just in case. But if you auto save anyway, that is not really needed.

Here is a short overview of the process to prepare for a new cut. I move the polygons via parameters. But you could move them as well in any way you like and use the Spline as a guide for snapping.
https://www.amazon.com/clouddrive/share/215vy2SGKYIpS4mXu6a4VJas0cjnd8faHUpG2JHolex
(Surface-cut.mp4)

If the original model uses a Subdivision Surface, you might need to “weight” the new edge. (See model)

Enjoy your weekend.

Thank you for the quick response!

Your files definitely look like what I need, although I’m still wrapping my head around exactly what you did.

A couple of questions:
My model is fairly low poly in a subdivision surface. The current topology is not optimal for what I need to do. In order to make the incision in the proper size and location (attached image), I need to add some cuts to some of the polygons in those areas.  My uv skills are woefully inadequate so this is a very basic question - Can I add cuts or subdivide the polygons just where I need more detail without screwing up the existing uvs?

I apologize - I think you may have answered this but I think I need further clarification or detail. 

My other question at this point is could you do the point morph and uv morph in the same tag or is what you did just to have separate control over the timing of each happening?

Hi Sapphire9,

With a low res model like this, you need to look into other options.

The first idea would be to place the character into a Subdivision Surface. Then animate the camera, or if it is all still, define all camera angles you need.
Then use the Surface deformer and place a Plane onto the area that needs the animation. Lined up in a way that a line of edges is along with the procedure. Use the “Current State to Object” to get that patch shaped like the body.
Place the material onto it and use a texture as an alpha channel to get the boundaries as a transition. With the patch, only the whole workflow will be much simpler.
Both parts will be then composite to create the idea that it was one object at any time.

If the instruments used to perform that surgery cast a shadow, these parts could cast a shadow on the whole body.

To your question: I would separate the UV, and Mesh PoseMoprh set up. Each slider would contain both data sets, which might lead to less control or even trouble. Try on a patch if the UV data needs to be changed at all; since the path would produce much denser UV information, the stretches of the skin might look natural without any further manipulation.

With the patch, you will feel much more comfortable creating this visualization.
Here is a dummy scene (I have offset the patch to demo it, this offset should be zero in the real set up)
https://www.amazon.com/clouddrive/share/qrpe5oL5NzLR3cqezPTNwLxI0NOG2dcpfNbZHSi22RM
(CV3_S24_drs_21_ANsg_01.c4d.zip)

All the best

This is great (and somewhat validates my struggles with the existing geometry).  It also shows that I have much to learn.
Thanks again for your time, especially on a weekend!  It’s VERY much appreciated.

Thanks a lot for the feedback, Sapphire9.

You’re very welcome!

Since we can recreate pretty much the whole world while adding even abstract and virtual visuals on top of it, I can say with certainty, we all constantly have to learn if we expand our field of work.

I believe it is safe to say that the most challenging part is to stop thinking with real-world parameters and take advantage of the “magic” we have in 3D. All that counts is that we got the idea across to our audience that we wanted to communicate. How we get, there is not defined of chiseled in stone.

Enjoy the ride.

Very welcome philosophy and encouragement.  You are the best.

Thanks for taking the time, Sapphire9.

I learn from every question, so it is my pleasure to be on this journey as well.

My best wishes for your project.

Well it turns out I have one more basic question for you about the patch and then I’ll leave you alone.

Using the surface deformer I have a patch in place.  When you say to place the material onto it - I understand using the texture in the alpha channel to blend the edges but do I need to copy the uvw tag from the original model and manually position the patch in uv edit to get the correct portion of the skin texture so it lines up? Sorry I’m being so slow.

Thanks for the follow-up question, Sapphire9.

I might overdeliver here, and sorry if, but let’s have a brief look into UVs first.
To get 2D images (as they are all flat) onto 3D objects (only a few are flat), we use the UV(W) polygons.
Typically the polygons of objects rely on points defined in space by X, Y, and Z. To get a clear differentiation with “UVs,” we call this UV (W). The W is not used for images, but if a 3D shader uses all three axes, that is the one. XYZ ~ UVW.

Each polygon on an object has a representation in the UV space. This space is measured from 0 to 1. This means, if the image is hi-res or low in resolution, it doesn’t matter. But objects are different in size. So we have the first point of translation for the whole object/image relation.
The second one is polygon-based; every single polygon of an object has a “twin” in the UV mesh. This UV-Polygon defines the area of the image that will be visible on the object.
If we increase the size of the UV-Polygon (a single one), we show more of the image inside the polygon space of the object. The more we see, the smaller the details of the image will show up.
Now do the little drill of post #9
https://www.cineversity.com/forums/viewthread/3551/#13850
(I hope the S24 interface is not in the way to follow along.)
This is usually the drill I do in hands-on classes, and the key is that you can see how moving a UV point will change the outcome for the object.
Typically 10 minutes are enough to have that “click” moment.

So, to your question, can you move a UV tag from one object to a different object. No, you can’t. The UV is an exact representation of the amount and nature (triangle, quad) of the polygons based on point numbers and sequences. Which makes them incompatible.

Since you have to deal with skin, you have many “wiggle” room there. The “texture” of the skin in that area is not changing too much.

If you have a problem, I will send you an upload link and prepare it for you, based on your model and how it is textured.

I’m sure it will be apparent to you in no time; just do that little drill.

Cheers

P.S.:

I updated the screen capture and the file, so it fits with S24. This drill is essential! So, it is good to have it with the current interface.
UV-challenge UV-Drill
https://www.amazon.com/clouddrive/share/vQug7lfPl8BoMHBNPGMewpOvQFeX2TbVmZ9j39uXO5t

Enjoy.

Thank you again!
I will leave you alone now.

I know how it feels to take some time to get things done, only to get stopped midway.
I’m happy to help. It never bothers me.

Have a great Sunday!

You have a great Sunday as well, if it’s still Sunday where you are!

I realize now that when you said to place the material on it, I got hung up on the wrong thing and wasn’t thinking at all about the “wiggle room” I have with the skin texture.  I definitely need more sleep but I appreciate all of your time and willingness to go back to basics.

OK, now I’m done:)

Thanks for the additional information, Sapphire9.

Whatever I write here is always written with the idea that many people will read it (all kind of skill-levels). When you write -basics-, I hope it didn’t felt that I evaluate anything here.

I certainly know that sleep deprivation will lower the depth of creativity and the ability to confront obstacles a lot. Limiting the amount of sleep is not paying off in the long run.

Enjoy!