Okay, it works or it could work. I'm trying to figure out an easier way to do this.

I tried using ONE model with the text of the sign and made it into an explode/breakable object. The problem is that all of the letters fall off or "explode" the same way at the same time. I have the back of the sign or the board, in the same model. In the chor it is resting on the ground so it doesn't fall. However the letter's bones are higher up. I would like them to "stick" to the board until some object hits the board or the letters. Then I would also like to have each different letter with a different amount of "stickiness".

I'm thinking the only way to do this is in the chor with individual letter models. I could create an "alphabet" of models, assemble in the chor and use links (I get sleepy just imagining this process). If that's the only way... I may cut back on how many signs I have in the final animation. Maybe I only do one or two instead of all of them (there's like 6).

There is however a very interesting idea that just now popped into my head... put "ledges" on the board model and actually have the letters "rest" on those ledges. Or I could add little "gizmos" to the back of each letter that rests on a ledge (just like a real sign board! Cool!). Still I can't have each letter with a different "force" needed to cause the letters to fall off. that is why I think I have to use the individual chor letter models technique.

Anyway, if anyone knows a better way to do this than the ideas described above let me know.

p.s. Oh, and by the way, I love newton physics. I can't wait to create some cool marble roller. I really want to try and get some marbles to shoot through the air over a long distance and land back on a track... cool.

-vern

Well... it works!
I split the sign board into sections that hold the letters. I leave a gap between sections. I then assign a "Newton_" group to each section but just one "Explode_" section (so the sign doesn't break but the pegs still rest on the gap).

I then put pegs on the back of the letters. I assign a newton group for that peg and assign a higher density to the letter itself. If I want them to be "looser" or "tighter" I just either scele the x and y of the peg so it can slip out of the gap or I can shorten the peg so the density of the group pulls it out. I think this will work GREAT. Still a ton of set up but less than assembling in a chor with individual letters and assigning all those newton linkages.

-vern

A quick dirty test. Some issues. I only did two letters with "pegs" as a test. I may need to make the gabs more like "holes", or maybe not. Sometimes the letters slide out the side instead of popping out the front. Will work on that. Still have some issues with ground plane location for parts of the model. The letters are "offset" on the Y axis. The board is perfect. I'm not sure where to put the "center" of the model because the board is behind the letters. I suppose the bones for each letter have to be exactly in the center vertically? Will do some more tests. I think I will try the "calculate COM" see if that helps. I also plan to fiddle with the friction. This should help make the letters "stick" more. Some will initially break free and others will stick. Will raise the damping as well.

Overall I'm THRILLED with the results. I can reuse the letters I think for different models. Can't decide which is more work, boning all the text or rearranging the letters. If I get one sign completely perfect moving the bones around to spell different words should be easier.

Click to view attachment

-vern

HeyVern!

That looks COOL! You are becoming a 'Newton-MANIAC'! (Great, another mania to your collection...) Forgive me if I missed this as I skimmed thru your above posts, but did you know that once the letters are simulated you can select the newton keyframes for each letter and offset them in time, so they don't all fall at once- if that is what you are looking for... if not- nevermind!

Thanks John.

Actually the letters won't "fall". They will ALL be "pegged" to the board. Each letter will have a longer or shorter peg to determine how well it "sticks" to the board. Some pegs will be thinner, some thicker. In the sample above, only the "T" and the "S" have pegs that fit into a groove on the board. What I've proven in my sample is that the "T" has a longer peg and falls out slower. The "S" has a shorter peg so it falls out more easily. They don't fall out unless the board moves or is hit by something (that's why the box drops on the board). They would jiggle a little but only fell out after hitting the board with something.

Once I have all the letters with pegs and adjust the friction and "density" of the newton groups of the letters I can control the final result. I want a sort of random assortment of letters to pop out. Some will still stick the board but others pop out and fall. Keep in mind that the final sign will be on a tall stand and the letters won't be seen hitting the floor in the final credits sequence. I've decided this is going to be a lot of work and will only do a few of the sign board instead of all of them.

The most absolutely amazing thing about newton physics is how freaking REAL it is. I put a very very thin groove in the sign board. It even has a back to it so you don't see the grooves as much. The pegs fit into the groove snuggly but there is a small space around the peg. There is very little space and yet newton correctly has them spin and wiggle realistically to fall out.

The key to this for ANYONE wanting amazing newton results is.... Newton Groups!!! Those things are AMAZING. You have a regular group for a shape but by subdividing the shape with "Newton_xx" groups you can define intricate cutouts and protrusions. I did this on some of the letters, lke the T. Creating a newton group for the top cross of the T so it would hook and fall correctly.

Most of the jittering at the end is from letters that DON'T have newton groups and have trouble coming to rest. Before adding newton groups to some of the letters they all behaved oddly.


-vern

I've NAILED IT BABY! WOOOOHOOOOO!!!! YEEHAAAA!

Click to view attachment

Finally! I know EXACTLY how to do newton physics and make it work correctly. This is a no brainer for those in the know probably but the key is to CENTER THE BONES on the volume of the mesh and make sure the whole model is centered properly. It's not as hard as I though... it just means you can't be "lazy" about modeling and where the bones are. I thought that was the case... no, I sort of knew that was the case but I didn't realize how extremely important it was. Even the smallest offset would cause things to not land right or interact incorrectly.

I figured a cool way to do this. Select the mesh that is assigned to an "Explode_" bone. Put markers at the center point for all axes. Then in bones mode just move the bone to align with those markers. Once I did that for all the letter shapes... MAN everything worked GREAT! There's an idea for a plugin... a plugin to center Explode_ bones to matching group meshes.

I increased the friction on the newton property for the model and I also made the pegs more "square" instead of round. Round pegs rotate around inside the gap. There will be a silver frame around the sign to hide the "gaps" for the letters. I will probably create a model with gaps through out like a real sign so the letters can be inserted and the sign will render like... well like a real sign board. I still want to make the letters "stick" more but that's just tweaking. I plan to create an entire alphabet and provide it to the AM community for fun and games with newton physics. Each letter in it's own model file so it can just be imported into an existing model. This will bring in the groups and bones for each letter.

I still have not worked out a simple solution for easily changing the "length" of the pegs so different letters fall out easier than others. I was going to use a bone to shorten the letter and maybe have a constraint on the letter bone to translate the appropriate amount so the center of that letter is maintained.... awful lot of effort though.

This will be my last post update in this thread now that it is solved... uh... thanks for the help? I'm kidding. Your feedback is incredibly inspirational.
I will continue to update this project in my "Change Your Pants" topic in the Vern's World section:

http://www.hash.com/forums/index.php?s=&am...st&p=260577

-vern

An easier way perhaps is to select the mesh with the scale thingy and with "show properties" on. Note the pivot x,y,z , and then in bones mode, use those values as the start of the bone's position, change rotate values to 0,0,0 (or whatever it has to be)

plug-in of course would be the easiest - but in the meantime... you is the plug-in...making it easier for the rest of us.

Good tip Nancy... but...

... uh... you must have me confused with that really young guy who can see a tour of a city from a helicopter ONCE and then draw it in perfect scale from memory. I don't have a very good memory and there are like 30 of these jobbies to center bones on. I can put in markers for nearly all of them at one time and then I don't have to remember the positions. Fortunately all the letters share the same z postion (as long as the pegs are the same length as they are now) and a lot of the letters share the same y position. Basically there are cap hieght letters (i, k, t), and small letters (a, c, s) that share the same Y position. I mark those that are the same and then the x is easy marking from the front view. Then it's simple to just go into bones mode and start moving all the bones. It's way faster doing it by "eye" zoomed in on the bone than typing in the properties.

Rather than a plugin it would be nice to be able to see the center point of the mesh controlled by the bone while in bones mode. This would be nice even without needing it for newton physics.

-vern

O Great Plugonian, sir - yes - twas ME who was confused. (I saw that program - fascinating!)

For that many meshes, tis easier the way you're doing it...

I would never do it the way I suggested - 'cause I would eyeball it - even without using markers (good enough for govmint work) - I thought the bevel-ly attentive among us might prefer to know the coordinates when nothing short of parallel universe quarky-time precision is acceptable...

I have a new "wrinkle" (forgive the pun). At the end when the credits say "change your pants" I would like to have a pair of cloth pants hit and land on the sign knocking off some letters... but... uh... you can't simulate cloth and newton physics at the same time!

How would I go about having a cloth object hit a newton object and have all the physics work together? Could I simulate the cloth first... then simulate the physics... then RESIMULATE* the cloth? No, that won't work because the cloth might not knock the letters off the same way... <sigh> quite a pickle.

-vern

* not reassimilate, there are no borgs in this animation.

Could you make a single muscle pose (per letter), where 0 is the normal stubby version, and then the length increases as the pose gets to 100%?

Then you add the letter to the chor, set slide the pose value in frame 0, done? Or am I not understanding what you are trying to accomplish? Or would that mess up the mass so the simulation doesn't occur properly?

The "mass" of the bone is important to newton physics. The bone for the explode group/bone must be at the center of the mesh that it controls. For instance I select a single letter mesh and note the exact center point. If the peg is shortened the position of the bone will be off slightly causing that letter to not land on the floor. It will hit it below or above it slightly depending on the bone position. The tricky part is that the peg and the letter mesh must be assigned to the same bone so it acts as one piece in the physics simulation.

I think I have solved this anyway. I can change the width and height of the peg instead of the length to achieve the same result. If it's "thicker" it "sticks" more. Thinner it will tend to fall out. I will make all the pegs the same length so that they can fall out if they are "loose" enough in the gap. Changing the thickness of the peg has no effect on the center of mass of the mesh because it's always smaller than the entire letter. Of course this will mean making all the pegs "extra skinny" to start. The letters are thin to begin with where the peg attaches and I don't want the peg to stick out beyond the letter. So I make extra skinny pegs. Close the gaps in the board to fit them snuggly. then I create poses for all the letters so I can easily change the thickness of the pegs (very very very slightly. Too much and the mesh penetrates the board gap and bad things happen).

I may... <sigh> I may actually try two pegs... just like a real sign board. this would allow them to "pop" out but not spin around which I think doesn't look like what I had in mind. This is not a huge change. It's still just adding a single "two pronged" peg to each letter.

-vern