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ygalula

Torn Ground WIP

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Hi,

I tried tearing the ground off this clip (background plate from "Death Proof").

While its not final, I"d love to hear your thoughts about it.

(Please ignore the obvious bugs on the left)

Thanks!

post-1179-127088315084_thumb.jpg

testSmall.mov

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looks very cool, but those pieces are more like cloth

how you project footage to geometry in houdini?? or maybe do you have some links where I can read about it?

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Shading isn't very good, but camera matching and projection looks quite accurate.

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I tried a similar thing too some time ago :)

it seems that you used a spring sop, it's cool but the pieces seems too much like cloth..

how did you broke up the road geometry?

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Thanks everyone.

Nibbler - You can project footage onto geometry by using the UVTexture SOP.

I do use something similar to the Spring SOP. It was meant to look a bit surreal.

I used a technique similar to the one posted by Aracid here:

http://forums.odforce.net/index.php?showtopic=5625&st=0&p=37945entry37945

How do you think I should improve the shading?

And another question - I tried adding motion blur, but I want to only see the blur caused by the moving geometry and not by the camera movement (since I already have motion blur on the ground texture). Any ideas on how it could be done?

Thanks!

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Hi,

I ended up using velocity vectors to create a 2d motion blur...

Would love to hear your thoughts about the new version:

small.mov

Thanks!

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It's getting better, but feels like there is not enough "holywood" in there :). What I mean is the occasional piece that flies a bit further (towards camera, bit cheesy though), it feels very uniform. Think about it this way: perhaps there are other things in the ground that would cause the creature(?) to slow down slightly, then speed up again. The resulting debris need more variation, specifically in the mass. If you are going for a different effect rather than something digging underneath, it might not be the best idea to try and match it that closely to the footage - most people will automatically want asphalt to behave like asphalt... unless you were to put some alien space ship with a tractor beam above it... but you get the point. Most people will probably feel there is "something wrong" with the simulation - even if that was your intention.

Also, your smoke needs more work. The opacity blending near the end feels to much like a fade rather than diffusion.. You might want to again consider the scale of things. Cigarette smoke difusses after a couple of seconds, but the amount of dust that you are kicking up would not diffuse as fast as that, it would probably hang around for at least a minute or 3 untill the finer dust has settled as well. Some pieces of debris would also leave behind dust trails as they are kicked up and flying through the air.

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ygalula: I don't understand how you match camera to this one in the footage? some addintional app?

the second version imo still have cloth like ground, give it more mass, also I think you should add more plates one ie with tiny sand, another with dust, another with more dense dust, there are also polygonal 90 degrees edges on the ground, for me it works when I watch many movies and breakdowns to get good motion, you can find some cool stuff on site like DD

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looks very cool, but those pieces are more like cloth

how you project footage to geometry in houdini?? or maybe do you have some links where I can read about it?

nice one!

I am also looking for some kind of tutorial, where camera mapping/projection is properly explained ...

any idea where to find such guidance?

cheers,

Manu

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Hey Yaron!

Looks very good! The only thing I feel might be missing is smaller bits of debris being flung around, like stones and grit etc.

Otherwise, nicely done!

Matt.

Edited by Matt_K

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Hi,

I added camera motion blur (as opposed to the velocity blur that I added previously), only to the edges of the geometry (since the road surface already has motion blur in the background plate), by extracting the edges in Nuke, and adding vector blur using the camera movement.

The new version is here:

http://vimeo.com/12506895

Yaron

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Good progress!

Seems like you have the big chunks, the dust and the general comp going. What I feel is missing is a lot more smaller debris, like gravel. I notice you have some gravel in there, but not much. Add more to it. It's just another element. To a certain degree you want to have a trail of dust and a trail of gravel.

Also the leading edge of the breaking up is very uniform. It would be cooler if you have it cracking open the ground in a zigzag pattern (kinda like lightning), rather than a uniform spherical force pushing everything up.

And as a last note, you have one level of fracturing going on. Once a big piece breaks off it stays as one piece. It would be nice to fracture some of those bigger pieces again after they have gone up in the air. As if they are losing little pieces around the edges. You can do this by choosing some of the pieces refracturing them and gluing them together.

In terms of lighting and comp, where are your shadows? Look at the shadow of the tree in the background. You seem to also have some "superblack" areas where the pieces just come out. Lift your blacks a little bit.

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Much better.

Should have asked this sooner... Are you rendering the chunks with motion blur? It doesn't look like it and imho would add so much to the effect. Those chunks are moving so fast and need motion blur to sell the effect. Either deformation blur if the terrain is pre-fractured or velocity based blur if you are fracturing on the fly.

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Thanks,

Actually I found it very difficult to render motion blur within Houdini, since some of the geometry is stationary (the velocity is 0), but the camera is moving and this camera move is blurring the projected texture (thus making it different from the background plate).

What I did was:

1. I rendered a velocity image and blurred the image in Nuke using those motion vectors.

2. I blurred the edges of the image using motion vectors from the camera move within Nuke (the edges of the crack was much too sharp without it).

Perhaps I should pump up the blur amount...? :)

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