Dynamics issue
Posted: 07 July 2018 04:49 AM   [ Ignore ]  
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Joined  2013-11-16

Hi

I have words made of sticks and I want to get them to build using a push apart and random effector with animated falloff. Then I need to blow them up using dynamics. I’ve put some of the pieces under a fracture object to test the simulation but nothing is consistent.

The test here just uses an animated push apart effector next dynamics is enabled (set to on collision) and finally a sphere pushes the words apart (Just some cross pieces at present).

Even though I’ve tried baking dynamics and setting initial states I have to turn the fracture object off and on each time and it will only play properly once. With the next play through the cross pieces don’t fly into the correct position (or out properly or consistently) even with dynamics baked and the viewport and final physical render don’t match (should both be set ti 25 fps).

I feel like it’s something simple that i’m missing.

Can you please have a look at the attached file and let me know how I should have set it up.

Thanks
Chris

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Posted: 07 July 2018 04:54 AM   [ Ignore ]   [ # 1 ]  
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Your website won’t let me post the zip file (Firefox on a Mac) How can I get it to you?

Also I keep getting messages about the Cineversity login and Forum posts not being secure BTW

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Posted: 07 July 2018 09:41 AM   [ Ignore ]   [ # 2 ]  
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Chris, Please check you “Private Messages Box” here on Cineversity, I have had send an upload link.

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Dr. Sassi V. Sassmannshausen Ph.D.

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Posted: 07 July 2018 11:44 AM   [ Ignore ]   [ # 3 ]  
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Just uploaded the file

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Posted: 07 July 2018 01:25 PM   [ Ignore ]   [ # 4 ]  
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Hi Chris,

I have rebuild the file, just the DAM-part, I leave the NO-part for you.

The flow goes from the Matrix Objects (v = vertical, X =  cross) via Inheritance to the Cloner. The Inheritance have the falloff, and the Parent Null object is animated.

After it is build, the dynamic is set to on.

To get all the sticks in place, I used a little polygon as structure, it is the Construction under the Connect Object, which serves then as Object in the Object Manager.

With so many sticks, I think the SDS is better on top.

Scene file
https://www.amazon.com/clouddrive/share/dJ0It9kUZ38wBmvU531OmGLz2FAx2T4vClPH6hef6MM

All the best

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Posted: 07 July 2018 05:45 PM   [ Ignore ]   [ # 5 ]  
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Thanks as always

Nice and logical (and much easier than what I was trying to do) - Should have thought of the inheritance effector. And using the connect object made everything much simpler.

A question - What was it about what I was trying that didn’t work? Using subdivisions below the level of the cloner? Ordering of elements? Having overlap of objects? Fracture object wrong? It would be useful for me to understand exactly what part/parts were causing the problem.

Also curious? Do you know if there is much more integration of Pro-render in the next release. Was using my new iMac Pro with radeon cards and it works reasonably well. Still too grainy at reasonable render times for animation and too many limitations but it’s promising. I’m looking at getting X-particles and maybe Cycles 4D so it will be interesting to see what happens with Pro-render in R20. Still a long way from something like redshift but then the issue is radeon cards in Macs and no CUDA.

Cheers
Chris

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Posted: 07 July 2018 07:42 PM   [ Ignore ]   [ # 6 ]  
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You’re very welcome, Chris, thanks for the feedback.

Using subdivision wouldn’t change the outcome. Please keep in mind that the SDS will generate much more polygons, and the Cloner will generate those again. With this in mind, to have a few child object, which are cloned many time, then the SDS is good as child. If you have many child objects under the Cloner, I might suggest to evaluate how much is generated before, and how much again with the cloner. If each child would be cloned only once, then one doubles the amount of polygons/segments, then SDS on top, small clones. If the amount of clones compared to the child objects is large, then it might be better to the clones, especially to render instances. If used in Dynamics, there is another point, if the dynamic needs to be calculated on a lower or higher mesh.

I did not found any Rigid Body Tags on any Cloner Objects.

If I understand your though process correctly with the set up, I would use a MoGraph Cache from frame zero to frame ~60 for the Fracture. I haven’t explored it deeper, so my estimate would be, that the Fracture child objects have no fixed starting point, but if they get stored in a cache, they “know” where to start from. Perhaps let me know if I’m wrong here. I just saw your model and the many parts, so my intention was to make it smaller. Please don’t take that as a critique, I’m faster setting things up than to explore all the many parts and find in the middle of a project the patches. I like to have control, and the Inheritance allows for a quick change (Matrix) to start from. It is one option, not the one and only idea.

I hope that helps.

If I would talk at any point about anything before any release, I would go against my ethics. It has served me well over a decade by now, there will be no word about anything from my side.
Let me put it that way how any “c4d - insider” keeps it: Who knows – doesn’t talk, who knows nothing – might talk a lot. There is nothing to add.

Have a great evening

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Posted: 07 July 2018 10:15 PM   [ Ignore ]   [ # 7 ]  
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Thanks Sassi

Learnt a lot from your feedback/help so all good.
One other question. Not too sure what the Xpresso tag does/is there for? Some kind of ordering?

As to Pro Render - That’s fine. All I can say is that there needs to be a huge increase in performance and integration for me to seriously consider it for production in R20.

Cheers
chris

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Posted: 08 July 2018 05:03 AM   [ Ignore ]   [ # 8 ]  
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Hi Dr Sassi

I realised the Xpresso was just to get the poly count.

But I’m also having issues with a few elements bouncing too much on the floor (Set the Trigger velocity high to stop the whole structure collapsing). Steps per frame 25 and iterations also 25 25 (higher doesn’t help).  Fiddled with linear and angular dampening but can’t get it to stop. Any thoughts.

See file.

Thanks Chris

File Attachments
DAMNO text_07.zip  (File Size: 309KB - Downloads: 4)
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Posted: 08 July 2018 06:36 AM   [ Ignore ]   [ # 9 ]  
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I also realised the viewport preview 9cached) and the software/hardware previews do not match a full render preview. Is there a way to get them to match?

Thanks
Chris

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Posted: 08 July 2018 10:04 AM   [ Ignore ]   [ # 10 ]  
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Hi Chris,

For suggestions about the application, please use this option here:
https://www.maxon.net/en-us/support/suggestions/

The viewports have a different algorithm than the picture viewer. If not, you would have to press after each action a refresh button. Caching everything should help here.

I have set so many parameter either back to default or to other values that it would take a while to explain it all, instead, here is a three cube example, that shows the three main ideas.
Example
https://www.amazon.com/clouddrive/share/474WLlLqeHHGYv18xJ7zdK2DOBDxYRz9A0EtDcMpjsm

Putting my mentor head on: For example, take the green Cube, duplicate it, move away from the other green Cube. Make certain all cache is cleared. Now check other parameters with the new green Cube. Increase decrease. This is an interactive way of learning the influence all the parts have. Yes, the is always an urge to start with a larger scene, getting the little tip to make it all work. But the next set up, you would feel more comfortable. Increase the friction, set it back, increase dampening, set it back, set both up, etc. Right Mouse click to read about in the Help Content. Then try again. This earned knowledge can’t be provided from 3rd party sources in this quality. It needs that work. The work here is that you ask a question, and that urge will give the motivation. With tutorials, one might nod and say: I got that. However – A week later, what was that…? Just finding something that works by playing “parameter lottery” will not educate in the way it is needed to feel savvy. Have you ever tried Aerodynamics-parameter? /mentor hat off.

The shape of the object is crucial. In this case I went with “Box” (just for speed), but I rather would use Moving Mesh on other set ups.
The key is to get energy out of the equation on the end. Please have a look, after you really have explored the three cubes. wink

I typically think that high friction values take the energy out of the scene, but it also prevents the objects to settle into the final position. The manual even states that low friction values lead to an early “stop”. However, rough wood boards on raw soil might work differently. Here I would se the Floor high and the wood boards lower, then the pile in it self can settle into its final position quickly, before that happens, the board friction can be animated higher (should be a second between both keys). I hope that makes sense. But as tried to explain with the three cubes, it is a result of many parameters, and the more one knows about, the less trouble is given to set them up iteratively to the final sweet spot. NOPE, there is no one size fits all, hence why I ask to explore this.

Scene file
https://www.amazon.com/clouddrive/share/CS8x6ToUrnXIrhwh0goUs3BKhGtTIfPPIouURellWl5

Have a great start into your week!

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Posted: 08 July 2018 02:08 PM   [ Ignore ]   [ # 11 ]  
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Thanks.

Good to see your thoughts and process.
Will have a play. Mograph tag seems to help (Bake after baking dynamics tag?)
Is it reasonable to keyframe an increase the linear and angular damping to stop everything once the dynamics have finished?

Otherwise have a great week.

Thanks Chris

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Posted: 08 July 2018 03:13 PM   [ Ignore ]   [ # 12 ]  
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Hi Chris,

The change of that parameter will stop things smoothly, it is like stepping slightly on the brake.

However, it needs to be done timely. If done too early, the rest state will perhaps reached later. Hence the slow increasing to smooth in that point and to make it invisible to the audience.


Cheers

======
Since I write in a forum:
As a right mouse click on the parameters unveils (via Help Content):

Linear Damping [0..+∞%]
Angular Damping [0..+∞%]

Damping is simply an “artificial” removal of kinetic energy from Dynamics - for linear damping and for angular (rotational) damping.

If, for example, you shake a container filled with objects and the objects don’t really come to rest, simply increase the Damping value to calm everything down.

Since Dynamics has no rolling friction, a sphere could theoretically roll indefinitely. With a defined Angular Damping the sphere will eventually roll to a stop.

In other cases, when the Dynamics system seems to “explode”, for example, damping values can be increased in order to prevent this from happening.

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Posted: 09 July 2018 02:11 PM   [ Ignore ]   [ # 13 ]  
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Thanks Dr Sassi

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Posted: 09 July 2018 02:12 PM   [ Ignore ]   [ # 14 ]  
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You’re very welcome, Chris.

Let me know if there is anything else, as usual: I’m happy to look into it.

ENJOY

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