Cineversity

Hi, I am trying to create an animation of “gas” moving through a single screw compressor. Similar to this:

https://youtu.be/M8GUGZT_A5o?t=163
https://youtu.be/oQ5Nxh61mpY?t=57

Please have a look at the attached images: https://www.dropbox.com/s/eaj8trabt3ilnru/screw-compressor.zip?dl=0

I basically just created a cylinder and overlaid it over the screw compressor and applied a material with a blue to red gradient. However, I’m not 100% satisfied with the result. In the final render, you can see the top edge of the cylinder, and it would be nice to have it gradually fade, so that you do not see the edge. Also, I like how in the first link I provided, each “channel” of the screw compressor gradually fades into red. How difficult would it be to achieve this affect?

Thanks!
Matt

Hi Matt,

I am terribly sorry that I answer with such a delay. I double checked my emails and nothing. No excuse, of course, just to explain why I why I missed it.

Here is the first part
Scene file
https://www.amazon.com/clouddrive/share/OVY8AnvEyAQM5IO4ZU6GhNpAiRdLJo1Tt9XLz5FPQpl

The “Helix” part could be based on the rotation, as space becomes smaller with the movement. So the color could change (XPresso). I have to experiment a moment with some setups, as the wheels cut these into two parts, red and blue while revolving.

More soon.

How DARE you take more than a day to reply! Haha it’s totally fine, no worries! I just appreciate you’re help and always nice to see how you would do things

Side note…will you be attending NAB?

Matt

Thanks so much for understanding, Matt. I think I do it at least once every year. Shame on me! I have to get better than that.

Sorry, I have no idea if I get invited to NAB. I would love to go, it has been a while, at least for Las Vegas. (At NAB New York, I had presented twice last year.) We had a great crew at the booth. I have nothing but good memories of any NAB, especially in ‘06, when MoGraph was introduced. MoGraph got this year an Academy Award (Oscar), I’m so proud to be from day one on board with it and help to make it grow since.

To your file, yes finally, it took me a few hours to find something that is relatively quick to explore and easy to share. (I have examined this area a little bit this evening.) I have created three different approaches, whereby I think that version …_21.c4d is the simplest, given the target here.
Please have a look
Scene files and screen capture
https://www.amazon.com/clouddrive/share/pYOh94hgFbL8adLda0kyBkmeaO8oCEx0RmFX6pdT4EB

The idea for version …_21.c4d was to create with a small set of Linear Fields a value space where any number of helix could be rotated in and receive the information needed. If I understand the principle of the compressor correctly, the gas moves into the helix and encounters there progressively less space, hence the increased pressure. This works on two sides, with a 180º rotation in the same way, which keeps several parts in balance.
Each side starts with low pressure and then it increases, which is per side created by two Linear fields. The Blend mode MULTIPLY allows here only for create than zero values of both have values greater than zero (otherwise zero times anything = zero). One Linear Field separates the 180º space from the other, and the one Field applies values only in a small area. This space is pretty much where the pressure is the highest. If the helix arrives partially on the other side, the pressure is low again, and the other two Fields start their influence.

Since all of that is kind of dynamic, but also in a way static, the animation needs some care. So, each requires its own material. Well, that pushes to see if the Fields could just serve something more complex.
Scene file
https://www.amazon.com/clouddrive/share/MQhkGcw89xWCr9mt6fzVe9buVNVXtaGnzHCOfVA0i2j
The idea was here to have six copies, and just one material and one Vertex Tag. It works. I even moved and rotated it, and it keeps working.

Let me know if that is useful for you or if we have to look into something else.

My best wishes

P.S.: Here is a Cylinder that contains the alpha and color information, purely on Shader and Field/Vertex options. A tiny amount of XPresso, and since the “Screw” would be metal/reflective that should look right, as the metal would reflect the color.

Scene file
https://www.amazon.com/clouddrive/share/xlH6ZCxvOw1AqcLEiRHVhlYBNkl0CGKfuYal5z1dRAP
Screen shot
https://www.amazon.com/clouddrive/share/UcEyiVtMzSQObd6MAcfJuABQf4iEkqXqoTRwZqUPbr6

Enjoy.

Wowsers! You must have put some time into this! Your first and last examples I think were the easiest for me to understand. Your brain is on an entirely different level I think than most haha. I really appreciate the time you put into this. Your example scenes will help immensely as I put together the final animation.

THANK YOU!

Thanks a lot for the kind feedback, Matt, and you’re very welcome.

Each animation can be done on different levels, like the gas would really move (using Volume modeling even more) or just a simple texture and fool the eye. I like to share as many options as I can so you can pick.

Last night, after working through these examples, I had at 1am another idea, like “doh!” it could be much more simple. (But I had to take a little nap first…)I will set up an example and check if I was not a “cat-brain” at that hour or if it really works.

I will post it as soon as I have streamlined the idea.

Talk to you soon.

Oh okay thank you so much! You’re very helpful!

Matt, here is the texture that could be the simplest version I can think of at the moment.

Scene file, screen-capture
https://www.amazon.com/clouddrive/share/VOaIQ918OPIo5eX0cRWyVIhkYkpUDpmETPwIm2ZqOzc

I have just set up the texture, so it is repeated once, for the two areas where the pressure is created (180º apart). As that gradient would move with the object, I have to counter it with a Range-Mapper.
The Angle of the gradient should be set in a way that each of these helix-elements has nearly a single color. When space is getting smaller, the pressure increases and the color changes.
This could be part of a larger object and then used in a Polygon Selection, to separate it from the “head” of the texture, where it is just blue. To make it more blurry inside, a second object might help, as shown in my initial post here. I could also think to have a more blurry texture inside of that color and gradient object.
I will explore the last suggestion a little bit and share a file if that works.

All the best

Or even simpler, just fooling the eye:

Scene file, screen shot
https://www.amazon.com/clouddrive/share/FKlR7Lv45EOjXB3ELbI9G5ZqxtzZlx2q6vnToV9PiTZ

ENJOY.

Oh wow yes that is much simpler! Funny how sometimes just taking a step back and not overthinking it can result from this haha. Thank you so much sir! Very very helpful!!

Matt

Yes, Matt, this is spot on: “…a step back and not overthinking…”.

It is so easy to fall for the task of recreating what we believe to see. Even if I would like to start with the simples way, my philosophy is indeed that no simplification has value – if not all parts of the equation are known.

Anyway, I’m glad that you like it. At the moment you render it, you will see the effect of the internal Hemisphere to blur the parts. I hope I understood this correctly. It is, after all, an interesting task to have a texture faking depth perception.

Let me know if there is anything else, as I write and mean it, happy to look into it.

My best wishes for your project