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# 1 24-04-2008 , 02:53 PM
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Crashing rocks

I have a matte painting and want to create an extra rock face in 3d in the red area which I would like to animate crumbling and crashing away. Is there a way I can get a 3d object to do this in maya effectively.

Thanks,

Leon Labyk

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# 2 24-04-2008 , 03:46 PM
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Let me answer your question with a question that I ask all of my Jr. Animators:

Do you want to "just get it done", or do you want to do it right and make it look how you picture it in your mind?


I ask this because at the angle of the shot in your painting, plus depending on how detailed you want to make this, it won't be easy.
Not hard, but not super easy eitheruser added image

Also keep in mind, that what you're asking for covers quite a lot of disciplines:

3D-
-Projection mapping
-Camera matching
-Low-res modeling of the scene, PLUS your new rock wall that "roughly" matches the topology of the other rocks in the scene, and your new paintwork, so that when you project the new painting onto your new geometry it holds up when your camera is moved off-axis or violently shaken in 3d.
This modeling will also gain you a z-depth map sequence you can blur a bit in post for fog, or depth blur, etc.

Then 2D (Post):
-Camera data import into your compositor, if your camera moves.
-More paint (extension)
-animated cracks paint
-animated mask of the crack-plate revealing or leading the falling rocks.
-dust and smaller debris particles
-any post-color work you want to do.


So, now that you can see the road ahead of you, what would you like to do?

Let us knowuser added image


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
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# 3 24-04-2008 , 04:13 PM
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Yeah Rage is spot on.

You need to plan what your going to do step by step and set up a workflow. In a nutshell I would do the following

Set up a camera to match the camera that took the pic.

Roughly model the rocks in the pic

use the background shader and project the image onto the geo and adjust if needed so it fits.

Model the rock you want.

Paint a texture for the rock either based on the original cameras projection or multiple projections, bake the projections into the file node

Duplicate it and break it up using the shatter script bake the projections into the bits, you might have to do some more texturing on the bits.

Light to match the original photo.

Key the visibility of the full and the broken bits, then add dynamics at the point you want it to break up.

once its all going how you like, render the rock in layers, comp in post adding any other bits you need.

Theres lots and lots of steps in between but if you knock a low res previs up you can apply the same principles.


"No pressure, no diamonds" Thomas Carlyle
# 4 04-05-2008 , 05:23 PM
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Ok I have simply assigned the matte to a poly plane and modeled the rocks as seperate pieces of geometry. This way it will work a lot better with the previous shots and be easier. I will need to add a camera shake as the rocks break away at the start and there will be another when the character who is in the shot reaches the camera but I am yet to get to that as he is behind the rocks and will only become visable after the large rock passes the camera. I am trying to work out how to go about creating a simulation with dust and smaller debris to come down with the falling rocks 1st though. Also is there a way to create sun beams to shine out around the rocks and dust in this shot.

Thanks for your help and advice with this guys it is much appreciated. I would of liked to created the scene as a simple 3d model and made it identical to the matte by taking it into zbrush but this would of probably taken a good days work and this method should work fine if I can suss how to get these other little tweaks going on.

https://www.youtube.com/watch?v=F_3GFp8Dvo0

# 5 04-05-2008 , 08:46 PM
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Just fyi, I moved this thread to the correct forum as it is dynamics and effects relateduser added image

Second, regarding your dust and debris, your best bet would be to either do it in post, as it is just coming directly at the camera, depending on the compositor you are using.

Or, simply emit particles from your falling rocks, and maybe an instancer for smaller debrisuser added image

Good luck!


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
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# 6 05-05-2008 , 04:28 AM
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I would possibly go with fluids for the dust, just it lends its self nicely for something like that, if you have unlimited, and a mix of instanced debris.


"No pressure, no diamonds" Thomas Carlyle
# 7 05-05-2008 , 05:11 AM
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I have emmited particles from the object but cannot suss how to stop the trail coming from the rocks start point. I have tried messing with the min max distance value but this seems to change the distance the particles are from the object and now the trail being left behind. I had hoped to have the particles emmiting to a few metres from the rocks by the time they reach the camera.

Thanks for your advice so far ragecgi it is much appreciated.

# 8 05-05-2008 , 06:06 AM
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Could you elaberate a bit on how I would use fluids for the dust Gster. I am useless when it comes to dynamics and am yet to create something I have been able to use.

Thanks,

Leon

# 9 05-05-2008 , 08:00 AM
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Think I got it just needed to set key the rate particles/sec. Just need to try and get things perfected. Also is there a way to randomize the size of the particles that are emmited.

Cheers,

Leon

# 10 05-05-2008 , 08:38 AM
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Please don't get confused.
Fluids are never suggested for dust.
Fluids are designed for Volumetrics and Pyroclastic simulation, and not for pixel-sized dust and streaks.

The Point or MultiPoint hardware particle rendertype in your particleshape is specificly designed for dust and small particulate matter.

To stop the "trail" of particles extending from your rocks simply adjust the particle lifespan to a smaller value.

Adjusting the size of your particles is a little more difficult depending on your particle rendertype, and the look you want.

Since you also admitted to not being familliar with dynamics, I also want to warn you now that if you are looking for a turn-key or pushbutton solution, it does not exist, as every situation and effect is different, thus the customizable nature of Mayauser added image

I would suggest reading the following chapters in the help:

Learning Resources:
-Getting Started with Maya
> Dynamics
(This whole lesson area of tutorial instruction is designed for those new to dynamics, such as yourself, and is written to absorb easily)

..and for further detail and instruction please see:

Using Maya:
-Dynamics and Effects
-Dynamics
>Particles

Good luck!


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com
# 11 05-05-2008 , 05:00 PM
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Thanks for your help with this ragecgi think I have got it looking ok. Now I just need to animate the character who climbs out from where the rocks are crashing from.

https://www.youtube.com/watch?v=ZQLTcJNqFCQ

Thanks,

Leon

# 12 05-05-2008 , 06:11 PM
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THERE YA GO!

Sweet shot manuser added image

Also, now that I've had time to think about it, I believe what gster123 was getting at with his Fluids suggestion was the slight cloudy nature of dust that tends to also happen in these natural situations by adding volume in areas with clumps of smaller debris and rocks, etc.

In your case after seeing your animation, Fluids might be overkill considering your angle and the relative speed of the overall shot. By that I mean, that type of detail is not required for your quick simulation.

If you really want to push it over the top, your best bet might be to also add a pass of a simple, low opacity, particle software-cloud following your larger rocks comped in between your smaller particles shaded with a very low frequency stucco texture colored with greys and browns.

Looks great otherwise!

Good jobuser added image


Israel "Izzy" Long
Motion and Title Design for Broadcast-Film-DS
izzylong.com
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