Cineversity

Hi Guys,

I’m having an issue trying to duplicate Thomas’ blood flow tutorial.  When I create the animation I have two things happening.  The first is my playback is really choppy.  I’ve tried the different display modes and even in low wireframe mode it seems really choppy.  The second has to do with the the spline instance and having the blood cells follow the spline.  Using his settings the blood cells stay within the walls of the vessel until the beginning of the animation and then the cells exploded out and gradually fall back inside the walls of the tube (vessel).  I’ve tried a bunch of different settings (moving mesh, static mess etc.) but it doesn’t seem to change the effect.  I’ve made sure caps on the start and end are off and also tried lowering the x, y, and z values so that the spread wasn’t as great but it still happens.  Any thoughts on what I’ve messed up would be great.

Thanks again,
Paul Wagner

Hi Paul Wagner,

Typically—without a scene file it is just guesswork. Not really my taste. Perhaps you can share your file?

I watched the complete presentation again to understand your questions and of course with the hope to support you in the best way.

Why your “redraw” or fluidity of the editor view is slow, might be based on several things. The best would be to set up the scene with just “flat” cubes and test it again.

Leave light and materials for the test put of the scene, just to keep it clear. The “Subsurface Division” object that he introduced might request a lot from your computer, leave it off as long as possible. I would normally take the original object and set an initial “subdivision” and use the cogwheel right sided of the Mesh>Commands>Subdivision. Once that is set, the cpu has not to re-create the subdivision each time. With one subdivision (smooth) you get hopefully close enough to the dynamic needs of the model. There is always the option to use the Subdivision Surface later on this, but you save on subdivision then. The downside of my suggestion here is, that you lose the option to go back to the very low poly model. But perhaps you keep a copy and swap it out if needed. (Proxy workflow). He did it (I presume) for demo purposes, and his computer was (AFAIK) a twelve core mac).

Check if any “mesh” in your scene is dense, if so lower it and check if the scene speeds up.

Explode of the rbc (Red Blood Cells), or stay outside?
Did the “Follow Position” is set?

I can take a look into your file of course. My suggestion would be always to lower the clones if it slows down the redraw and fps of the screen.

I assume that you have set up your system so it is fast, e.g., if you have a fast graphic card, the preferences are set to use it. There is as well a quick check option if the GPU has all needed parts. Reflections, shadows etc should not be used in the set up phase, if your system slows down. I say that from experience of ten+ years getting files from others during teaching online, there is often light and heavy textures already in use, without need often. Just a thought.

Let me know what next step you would like to prefer.

All the best

Sassi

Hi Sassi,

Thank you for getting back to me so quickly.  I was playing around with the scene again and found that if I lower the clone count (per your suggestion) it does greatly improve the fps smoothness of the playback.  I also lowered the the subdivision renderer and subdivision editor settings for the rbcs which I think helped the smoothness of the playback.

With regard to the other issue (i.e., the rbcs exploding out from the spline tube on the start of the animation).  This seems to happen because of the rate at which the clones move along the spline.  In other words, if I lower that value then the rbcs down move as violently on the start of the animation.  Also, if I turn off loop then the don’t jump up off the spline path like the do when it’s on, however, then the clones of course don’t keep refreshing so the blood flow stops after (x) number of frames.  I checked to make sure that caps were off on the sweep nurb and they were.  I wonder if there is a way not to have the objects cluster on the spline path when the animation begins?  I’ll have to view the tutorial again and see if his rbcs start off all clustered on the spline or not.

Anyway, as always thank you so much for helping me.  You are great and I really appreciate the time you take to respond to these posts.

I hope you are having a nice weekend.

Paul

Hi Paul,

You’re welcome. Each scene has its own demands, but C4D has mostly more than one way to get something done.

I’m not certain if my little sketch will work for the scene or your needs at all. I have introduced the MoSpline here. It is based on the idea to have a way too long initial source Spline. The MoSpline is then set up so you can fine tune where the clones start, where the tube starts, and something that I like a lot, when the Effector starts working. I used it in the “falloff” section of the Random Effector.
In this way any rbcs that need to be influenced by an effector, can be set up exactly along the Spline and adjusted via “Start” and “End”. This allows as well that the effect is less strong towards the vein, if you set up the Falloff accordingly.
With that—less power to “digest” for the Dynamics (hopefully, again, this is only a quick “brainstorming”/sketch). Please note that the Sweep’s diameter is based on the MoSpline setting, not any longer on the diameter of the Circle.

I hope that helps a little bit to adjust the given great example of the tutorial with your needs or wishes.

Have a great weekend as well

Sassi

Hi Sassi,

Thank you for sending me this file.  This does solve the problem of the rbis jumping off the spline when the animation starts.  Very interesting.

Thank you again,
Paul Wagner

Hi Paul Wagner,

Thanks for the feedback. Very nice of you.

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As a side note, or a different set up:
Another solution to keep the rbcs “kind of” organized could be done with the idea here:
http://www.cineversity.com/forums/viewthread/1328/#4564

The u parameter in the Formula Effector is like the UV of the texture. It provides each clone with an “normalized” value from 0.0 to 1.0, based on its position. In that way you can set in math/formula when they provide a weight or perhaps when not.

Just to keep the options as wide as possible.

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Have a great evening

Sassi

Question?

At the end of this tutorial I was very interested in finding out how to slide the white blood cell with the soft body tag along the collider surface . What I don’t understand from this tutorial is without a align to spline tag on the softbody is how to make it move along the surface that it collides with?. The follow position doesn’t seem to connect the two. Is this all inside the cloner with an object mode?

Thanks,
Gregory

Hi Gregory,

I have prepared a little scene file. You might tweak the values of course. The question can be answered with the “Loop/Rate” option iside of the Cloner Object (Object tab)

Please have a look into the image (lower area)
I hope that works for you.

Let me know if there is another question.

Enjoy your evening.