Ask The Trainer: June 10, follow -up: truck loading container
Posted: 11 June 2021 09:19 AM   [ Ignore ]  
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The Truck: Container (ATT Jun 10, 2021)

There are certainly some questions. Please ask!

Preview:
https://www.amazon.com/clouddrive/share/39hLooWYVZzkOWNeIYA4GBfZ4xMlaxuIHd3W9dMlf1g
the discussion about the truck question starts here:
https://www.youtube.com/watch?v=ATEJsRHHblU&t=1750s

Charles asked a question during the Ask The Trainer session:
https://www.youtube.com/watch?v=ATEJsRHHblU
As I have experienced it many times, information comes in steps, and each iteration leads to new ideas.

Typically, we start with how we understand a specific question and then get feedback and refine it. I think we all work in this way. Besides that, we all have our preferred way to do things. There is often no right or wrong way, and it depends on many parts of the whole situation.

So, my personal way is based on the idea of control and the ease of communicating about it. What use has the most sophisticated solution when you need too long to explain it? When we have three or four solutions, we feel comfortable using what fits best to us as artists. Which is never a judgment from where I look at it. We just fill our creative library. The larger this library gets, the more we can work towards our visions as artists. So, please stay open to the great brainstorming that happens during the Ask The Trainer events.

Here is the version that I would do when the animation would land on my desk. I tried to keep the rig small and easy to adjust. You can see in frames 99 and 100 that I swap the Container. Which simplified the whole thing.
We create in Cinema 4D for a rendering, and this visual result is all I’m after. So, how we do this magic should always follow our very own ideas.

One null moves the object, while another (in the hierarchy) supports its orientation. This is the simplest form I can think of for now. I will go below in more detail about the main problem that this question contained.
Here is my take on it:
https://www.amazon.com/clouddrive/share/wMb61NcQwyNqYoBeq3ee0YyuEPq6aucqF2YLXXgiuJM


From my perspective, the core problem boils down to the problem of two “edges” of an object that needs to stay in contact with the context. Move the Container up the slide while keeping one edge on the floor.
A classic case is the connection rod between the piston and the crankshaft.
https://www.amazon.com/clouddrive/share/1qZGYW4R6h9L99NZRJXcHPIaI7hHZQsn0by8MEGa9N
Here, it is solvable with simple Pythagoras (or trigonometry…) since the crankshaft and piston are limited in movement (either rotation or up/down).

For a container with a moveable slide, that would require more math, and it becomes something where we lose 99.9% of our audience.

The example below is a first step, and kind of easy, given the complexity of the otherwise simple-looking setup.
Example 1 with screen capture
https://www.amazon.com/clouddrive/share/JPBs68r2Quej1dvyAahRGG7BKX92tqA6vvmtNaifcSW

Example 2 for curved slides.
https://www.amazon.com/clouddrive/share/Wx0yCoWdfSmKTQNAtJkf4pfwll1tS5zzcIUCi60opBL

I hope that supports future solutions.

Enjoy your weekend, stay safe, and thanks for watching Ask The Trainer.

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Dr. Sassi V. Sassmannshausen Ph.D.
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Posted: 15 June 2021 05:10 AM   [ Ignore ]   [ # 1 ]  
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Good morning (presumalbly) Dr Sassmannshausen.

I haven’t forgotten about this issue.  I’ve tried a number of null based solutions to extend your work.  I did manage a version that kept the container on the rails without swinging below them, but by that time the number of nulls had increased to the point where attempting to reparent the container was quite beyond me.

After pursuing that for some time I went back to the dynamics. I realized that my mesh shapes were both incorrect and the object hierarchy was also incorrect.

I fixed the meshes and the hierarchy, tossed in a motor to pull the container up the rails…and it worked!  Almost.

My last issues are two-fold:
1)  It appears that animating the object A of the motor object has no effect, as such I have to always have the container connected to the motor.  This will make handling multiple containers in sequence very…tricky.
2)  Setting the parent for the container via a parent constraint tag also seems to have no effect.  This makes moving the container after loading very difficult.

I am including a link to my current c4d file if you would care to take a peek and perhaps offer a hint on how to overcome the two issues I would greatly appreciate it.

Loadtest-H.c4d

P.S.  I think I have been remiss in thanking you for your help thus far.  So.  Thank you, I do appreciate your time.

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Posted: 15 June 2021 09:47 AM   [ Ignore ]   [ # 2 ]  
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Hi Charles,

Thanks for your file!

Before I share the requested solution, which was fun to do, I can’t avoid saying it. Because I want you to do whatever you want and not having anything in your way. Deal? OK!

Let me start with my mentor hat on. To get that out of the way.

Having provided a complete setup on how to animate this, I know that it is possible. I find that using Dynamics here is a way to avoid learning what is needed. This means that it is something that goes kind of against what I think is required. Furthermore, it is a classical case where the “New Solution” might produce more problems than the problem you try to solve here.

My philosophy is: A problem comes back until it is solved.

Dynamics are not really the answer for this mechanical animation.

So, my problem is that you asked, and I will solve that, as mentioned in two lines above.

Mentor hat off. Finally. wink

So, with that all said, let’s do it with Dynamics anyway, as requested.
To work in 3D often requires leaving reality for a moment alone and visualize what you really want. You want the truck arriving and loading the container, then leaving. With Dynamics.
Here is an example
https://www.amazon.com/clouddrive/share/dHdt6bHeTFGd8LuTqlhBzf7QNejpJmbEeoVIQI8e1XS

It is the simplest dynamic setup I can imagine right now.
The “Michael Bay Fluorescent Green” objects will not be rendered. They are just dynamic cheats.

Enjoy

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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Posted: 15 June 2021 10:06 AM   [ Ignore ]   [ # 3 ]  
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Hi Dr Sassmannshausen.

I completely understand your stance, and quite frankly I support it.  I do a lot of team mentoring with junior/intermediate programmers and have seen many individuals trying to sketch around an underlying issue.  It never works.

In this case I think that what my goal for the scene is will justify the dynamics.  Given the frequency of container changes in the first scene, and any others in the future, I am desirous to reduce the number of manual keyframes required, and hence the potential for mistakes. 

Once I have the first draft of the final scene I will be sure to send it to you.

I look forward to seeing your file this evening.

Have a great day.

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Posted: 15 June 2021 10:21 AM   [ Ignore ]   [ # 4 ]  
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Hi Charles,

Thank you so much! It is nice that you can go with this so easily.

My firm belief is that tech should never be in the way, so we need to know it well to take advantage. I’m not really into “I learn it when I need it”, as that limits one’s creative library.

The main question would be how to get these steps into standards, like facial expressions. Computers are good for repetitive stuff…

One thing that I have seen over the decades, there is very little taken advantage of filmic montage options in 3D animation while learning it. (Kuleshov!). We are in the business of producing images in our audience’s minds. Not so much on the screen, if you get my drift. It can make your life so much easier.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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Posted: 15 June 2021 12:30 PM   [ Ignore ]   [ # 5 ]  
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Here is a rig that I think is universal.

It works even as Animation Clip. The take-over point needs to be adjusted, and the size/rotation, to the given truck.

But it contains all steps, and since containers are either 20 or 40 feet long, perhaps two different rigs are needed.

Files
https://www.amazon.com/clouddrive/share/pcceYjk6vAmZ6cdmNpmTLAK13Qyu5gm20x4xTCUia2S

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Dr. Sassi V. Sassmannshausen Ph.D.
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Posted: 15 June 2021 01:53 PM   [ Ignore ]   [ # 6 ]  
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It appears we are going down very similar paths.

I have two motion clips (load/unload) that are both currently working and getting me very close to almost keyframeless animations.  I am keeping your fluorescent green blocks as a substitute for trouble shooting why the set parent constraint seems so flaky(or my understanding is flaky…).

In my neverending quest to be more lazy that the previous day I am attempting to write xome expresso code to determine the closest container’s hook point, and if that hook point is within 20cm of the trucks latchpoint.  If it is within 20cm and the truck does not have a container loaded (stored in user data on the truck at the end of the loading animation clip and cleared at the end of the unloading animation [The latch point is more than 20cm away after the unloading animation clip]) then the I can set the ‘Object A’ reference on a motor to load the container during the loading animation.  If there are no hookpoints within 20cm then ‘Object A’ can be cleared.

Sounds good.  Unfortunately I have yet to find the concept of flow control within expresso.  Each variant of switch/compare conditions simply output a different value rather than being an actual flow control element.  I may have to give up on this one :(

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Posted: 15 June 2021 06:08 PM   [ Ignore ]   [ # 7 ]  
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Hi charles.horan,

This is a new question. Please use a new thread for new themes. The readability of the forum will be low if we keep going and going. Thanks for considering.

Here is a little XPresso setup.

Click on the XPresso tag: The Reset option will position the torus to the Start-Null position.

If the Sphere’s speed is larger than the 20cm/frame, it will disconnect the two.

https://www.amazon.com/clouddrive/share/Qzux9gdxnE4i0ojLl9EMxJ2OHavEFNITjDOuCk5BSK0

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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