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Breaking things
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Breaking things // Archive: Tech Forum
Post by W!ZARD // Feb 17, 2008, 3:08am
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W!ZARD
Total Posts: 2603
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I'm dabbling with physics and I have a picture on a wall - I've got the picture falling from the wall quite nicely but I want it to break into it's individual subgroups when it hits the ground.
What do I need to do to get it to fall apart when it hits the ground?
According to the manual (Chapter 10.2.6) "If you assign physical attributes to an object with several parts, each sub-object (that has a Mesh and Matrix) of this object has it's own set of physical attributes represented by the PhysObj object (which belongs to the given sub-object). The overall attributes for the whole object are represented by the PhysGroupObj and are computed from the values of the PhysObj objects that belong to the individual sub-objects."
Whilst this techno speak (somewhat surprisingly) actually makes sense to me I cannot figure out how "assign physical attributes to an object with several parts". When I assign physical attributes to the object the PhysObj and PhysGroupObj do not appear within the object encapsulator(as they do in the Atom scene).
So this is a two part question - How to make the PhysObj and PhysGroupObj appear within the Object Encapsulator like they are supposed to and how to get my picture object to break a part when it hits the ground?
Any insights here would be very much appreciated.
Thanks in advance
WZRD |
Post by frank // Feb 17, 2008, 5:32am
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frank
Total Posts: 709
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Check out this thread:
http://forums1.caligari.com/truespace/showthread.php?t=1234
That may be what you are after. |
Post by W!ZARD // Feb 17, 2008, 5:50am
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W!ZARD
Total Posts: 2603
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Thanks Frank - an interesting thread. I've been pottering about with it while waiting for someone to rescue me and I'm starting to make some progress.
Still can't figure the PhysGroupObj thing though |
Post by jane55 // Feb 17, 2008, 6:28am
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jane55
Total Posts: 5
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Still can't figure the PhysGroupObj thing though[/COLOR][/FONT][/QUOTE]
Hi Wizard,
Not sure how this works on Model side but on Workspace side the group/sub-object attributes are set automatically when you 'Add Phys. Attr' to the group. If you look inside the grouped object you should see the 'PhysObject' node with a 'Physics GROUP Attr' attribute. If you then look inside the sub-objects, they should also each have a 'PhysObject' node but with a 'Physics Attr' attribute instead of a 'group' attribute. I think this is how its supposed to work (I'm new at Physics too). |
Post by frootee // Feb 17, 2008, 6:29am
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frootee
Total Posts: 2667
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Wizard:
Initially, your object will not have physics attributes.
0. Select your object either in the 3D view or the LE.
1. Add physics to your object if you have not already. At this point, you should now see a Physics Group Attr attribute on the node of your object,
as well as each of your subobject nodes.
2. Go inside your object in the LE. You will have a PhysObject node.
3. Click on Exp tab of PhysObject node
4. Click the Breakable checkbox to enable it
5. Make sure your object is above ground, for a quick test
6. Start the simulation.
7. The object should break apart on impact with the ground.
Froo
EDIT:
If you have an object composed of several objects:
If you apply physics properties to the 'Main' object, these physics properties are assigned to all the subobjects.
You can then go inside each of these subobjects, and modify the physics properties for each of these subobjects, individually.
You can also deactivate physics for each individual subobject if you wish.
So, take the chair scene example. I just unchecked the Active checkbox for one of the cube nodes inside the chair node (selected at random).
While the rest of the chair fell, this part (the front legs) remained in place.
As another example, you can adjust rotation acceleration for individual items, for special effects. In a nutshell, all the physics properties available
can be individually modified for each subobject.
HTH!
Froo |
Post by W!ZARD // Feb 17, 2008, 7:34am
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W!ZARD
Total Posts: 2603
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Thanks jane55. What you've written sums up exactly the way it 'should' happen but it doesn't:( (Welcome to the forum by the way).
Froo - "1. Add physics to your object if you have not already. At this point, you should now see a Physics Group Attr attribute on the node of your object, as well as each of your subobject nodes. "
What happens is I add physics to my object (seven sub-objects) by selecting the grouped object and clicking the Add Phys Attr icon. Going to the LE I click the orange square to enter the object encapsulater and this is where I should see all my sub-objects PLUS a PhysGroupObj but what I see is just the sub-objects as before with no PhysGroupObj.
However entering any of the sub-object encapsulators I see a PhysObj as I would expect. The object responds to the physical simulation but not as smoothly as I would have anticipated.
Additionally when I record Key-frames the playback action is so jerky as to be totally unusable:( - again, not what I expected.
So I guess the question is - where is my PhysGroupObj and how can I get it to appear in my LE?
I tried using this object and a different test object all alone in a new scene, I've tried starting tS in it's Default config I've tried dragging and dropping physics attributes from the Physics - Solids library - I've even tried bowing three times in the direction of California - the results came back the same each time - no PhysGroupObj object:(
Any suggestions welcome |
Post by trueBlue // Feb 17, 2008, 8:00am
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trueBlue
Total Posts: 1761
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Humm when you first enter your Encapsulated object you do not see the PhysObject? This would be the PhysObject for Group. I notice that when I select this object I can not add it's attributes to the Keying panel but I can add each individual object's PhysObject by selecting them first. |
Post by frootee // Feb 17, 2008, 8:10am
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frootee
Total Posts: 2667
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in the upper left hand corner of the LE is a white icon. left click that, then select Arrange. That will arrange all the items,and your PhysObject should be made visible. It should be there somewhere. :) |
Post by jane55 // Feb 17, 2008, 8:17am
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jane55
Total Posts: 5
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Thanks jane55. What you've written sums up exactly the way it 'should' happen but it doesn't:( (Welcome to the forum by the way).
[cut]
What happens is I add physics to my object (seven sub-objects) by selecting the grouped object and clicking the Add Phys Attr icon. Going to the LE I click the orange square to enter the object encapsulater and this is where I should see all my sub-objects PLUS a PhysGroupObj but what I see is just the sub-objects as before with no PhysGroupObj.
Hi again W!ZARD - thanks for the welcome.
When I first applied the 'Add Phys Attr' to a group object I couldn't see the PhysObject node for the group either and thought there was a problem. Turned out it had been (automatically) placed in the LE quite a distance above the sub-objects. After I enlarged the LE window, there it was all along - it had just been hiding from me :rolleyes:
Best of luck solving your problem - sorry I can't offer any other solution. |
Post by jane55 // Feb 17, 2008, 8:23am
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jane55
Total Posts: 5
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Ah frootee - you posted while I was still writing mine. Same solution. Hope its this simple for Wizard to fix. |
Post by rjeff // Feb 17, 2008, 8:42am
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rjeff
Total Posts: 1260
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Hey wizzard there is a plug in that came with the "paks" that TS offers that blows stuff up. I have it, but I have never used it. I do know that you can set the rate of destruction as well as the pieces. Basically you send a projectile at the object and it blows up. If I am correct the projecitle does not have to be visible. |
Post by frootee // Feb 17, 2008, 8:46am
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frootee
Total Posts: 2667
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Ah frootee - you posted while I was still writing mine. Same solution. Hope its this simple for Wizard to fix.
Hi Jane. Cool.
Sometimes I have trouble where, no matter how large I make the LE window, and no matter how much searching I do, using that box in the lower right corner of the LE window, I cannot find what I am looking for. So I click that arrange button and everything is brought into focus, though not necessarily in the order I like. For example, items which have links to each other are placed way far from each other. That's kind of annoying, though I can then see everything. :)
Froo |
Post by W!ZARD // Feb 17, 2008, 9:00pm
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W!ZARD
Total Posts: 2603
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Thanks for the suggestion folks but I already thought of that - I use the arrange function all the time - so much so that I often wonder why the LE doesn't arrange the objects automatically the first time you enter that level.
If I remove all physical attributes (or bring in a version of the model that never had them in the first place and select the object there are two ways to add physical atrributes - 1 is to drag and drop a preset attribute object from the Physics-Solids Library. The other is to select the object and click the Add Phys Attr. icon - at least that's how I understand it.
When I do that the object should automatically gain a PhysGroupObj object and the sub-objects should gain a PhysObject - again that's how I understand it.
What happens though is I get a PhysObject object at the top of the heirarchy when I open the encapsulator - the sub objects have no PhysObject - even when I 'Arrange' the objects. ASdditionally the object does not respond to the simulation.
I can get a response by adding physical attributes to each sub-object but it doesn't work very well.
It seems like the I]PhysGroupObj[/I] object doesn't get loaded - although it functions as advertised in the Atoms scene.:confused:
This applies in a new scene with nothing but my 7 part object in it.
So thatnks to all for the suggestions but I'm suspecting I need some new suggestions! All help is massively appreciated |
Post by trueBlue // Feb 17, 2008, 10:41pm
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trueBlue
Total Posts: 1761
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Yes I did see what you mention and I meant to note this as well. Even though the top level PhysObject is named PhysObject it is a PhysGroupObject. Seems that it gets renamed in tS7.5.1 You can navigate to System/Physics/Objects and see that it is named correctly. However if you notice at the bottom it does have the Physics Group Attribute and the PhysObject has the Physics Attribute. The Atoms scene was built in tS7.0.
PhysGroupObject:
11121
PhysObject
11122 |
Post by W!ZARD // Feb 18, 2008, 12:02am
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W!ZARD
Total Posts: 2603
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The Atoms scene was built in tS7.0.
LOL! Such a simple answer. Thanks trueBlue that explains a lot!
I'm having a bit more success now with a totally different scene I've made to test this whole thing out and try to get a good grasp of it all. |
Post by parva // Feb 18, 2008, 4:41am
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parva
Total Posts: 822
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break a box with 1000 objects :D
11132
11137 |
Post by W!ZARD // Feb 18, 2008, 4:57am
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W!ZARD
Total Posts: 2603
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Sorry Parva I couldn't get that to run for more than about 1 second but I did get the general idea.
Is that using trueSpace? |
Post by parva // Feb 18, 2008, 5:21am
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parva
Total Posts: 822
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yes something is weird there... I uploaded it as wmv now.
Yes truespace workspace with my custom skylight and one directional.
1000 objects in a 10x10x10 box. Breakable, looks first a bit strange but the collapse is nice ^^
The recording is incredible fast. 200 frames in less then one minute.
Unfortunatly no direct avi export so I built it up in "bmp to avi". |
Post by W!ZARD // Feb 18, 2008, 6:08am
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W!ZARD
Total Posts: 2603
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Ah that's cool! The WMV works fine. Well it's clear you know what you are doing with tS animation and physical simulations - unlike me:(.
Pe3rhaps you could take a look at this WMV and tell me what you think?
I've set up the simulation and it works just fine as you'll see in the first part of the wmv - but when I set the Animation Editor up to capture keyframes from the sim it all goes wrong very quickly.
I've tried to follow the manual as closely as possible, adapting it to my scene but I'm not having a lot of success so far.
Any help from anyone would be appreciated. |
Post by parva // Feb 18, 2008, 7:40am
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parva
Total Posts: 822
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wohoo thats weird indeed.
Mmh, difficult to say. Have you the bridge on or something else created at model side?
Personally I didn't ever run into such problems but I don't work in model side and bridge is always off. Of course this has to say nothing, it could be also a problem at workspace but that the recording during phys sim is such strange with total wrong euler transformations is new to me.
Have you tried to rerecord the simulation? |
Post by W!ZARD // Feb 18, 2008, 9:47pm
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W!ZARD
Total Posts: 2603
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wohoo thats weird indeed.
Mmh, difficult to say. Have you the bridge on or something else created at model side?
Personally I didn't ever run into such problems but I don't work in model side and bridge is always off. Of course this has to say nothing, it could be also a problem at workspace but that the recording during phys sim is such strange with total wrong euler transformations is new to me.
Have you tried to rerecord the simulation?
Thanks Parva - yeah 'weird' is one word for it, I can think of several others, starting with frustrating :confused:.
I thought about the bridge too but checked that it was off so it wasn't using CPU cycles. I did try rerecording repeatedly with every combination of settings that I could think of always with the same or very similar results. :(
One other thing I forgot to mention - although the simulation runs fine (as you saw in the first half of the video) it stops unexpectedly and tS freezes for a while before eventually unfreezing.
I'll be trying again with it this evening but if anyone else has any ideas I'm open to any and every suggestion! |
Post by parva // Feb 19, 2008, 1:19am
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parva
Total Posts: 822
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First I thought it's a problem with the surrouning geometry.
Means the object around your physic simulated fractional window can be to close and create this strange behaviour but if your physic simulation runs fine and only the recording went wrong I doubt that this could be the failure.
The freezing has not much to say. Physic simulation can become expensive and especially in the situation I described above (objects near other objects etc.) many claculations are needed and cause sometimes errors.
Unfortunatly there is not a real indicator yet that says if tS is freezed or in a heavy calculation. |
Post by W!ZARD // Feb 19, 2008, 2:36am
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W!ZARD
Total Posts: 2603
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Well whatever was causing the odd behaviour is gone now. I saved out all the objects and put them in a brand new scene and everything worked like a charm - I'm a much happier chap now though it would be nice to know what was going on.
Thanks for your help Parva but it's all looking good now. |
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