View Full Version : Car Crash WIP

05 May 2010, 08:37 AM

A early test render of a personal project which is going to include in my reel. All functional blocks are there, ie. denting of the car body, lighting, shading, shattering of windshield and glasses, dust from the ground, motion blur, etc. I should be on the stage of final tweaking or re-tweaking some parts of it, so I would like to ask other artists c&c. So that, I wouldn't overlook some details and further improve it.

Please pretend there is a rock where the car hits. I forgot to render it=(.

All is done in Houdini, so it is rather easy to iteratively improve the shot.


05 May 2010, 03:24 PM
Is this going on an FX reel?
If so I'd rethink the presentation a bit. It just feels a bit strange to see a car slowly drive down a path just to show a quick pop of a crash. It's 6-7 seconds of driving and just 1-2 seconds of crash which goes by so fast you can hardly tell what went on.

You could safely cut the first 4-5 seconds of the car driving and perhaps right after the impact replay it again in slow motion from different angles (kind of like crash test dummy tests) to really show off your FX.

And why would there be a huge rock in the middle of the road that the car just drives into?
It looks like the bonnet pops up a fraction before the car hits but it's hard to really tell as it's all happening so fast and I can't frame by frame on Vimeo.
The dust coming off the wheels seems to pop a lot.

You might want to look at lighting the car a bit better too as it looks quite flat with washed out shadows but if you're concentrating more on FX then don't worry too much about it (though then you might also just leave out the environment)


05 May 2010, 05:38 PM
Wiro, thank you for your insights.

It should go into a Dynamic/FX TD and a Lighting/Shading TD reel.

I was thinking to render only one piece for both reels to save some render time, but I guess it doesn't get me to either end. There is a second part that the car is set on fire after the crash. And, I want to nail this part before starting the second part.

Your idea of slow motion to show off the crash is good one. So, should I tailor the pieces for each reel?

In the Lighting/Shading TD reel, the car could just pass by to demo the shader. And, I wrote a mia_material equivalent shader in VEX for Houdini Mantra. I think shader writing is important for a Lighting/Shading TD, so how to show the shaders writing skills in a reel? And, does rendering realistic fire&smoke important for a Lighting/Shading TD?

05 May 2010, 08:35 PM
This may seem nitpicky, but the first thing that stood out to me was how the front windshield shattered and flew out. I know it looks cool, but realistically, that wouldn't happen. Safety glass doesn't shatter into large chunks, and for most front impacts (even at high speeds) it's not likely to shatter and burst out like that. It's much more likely to burst from the impact of the driver's head hitting the windshield, but even then not likely to burst out of the car.

You should do a google search for 'Front impact crash tests' on cars. You can find some great reference material for how the car frame should respond to slamming into a solid object.

Edit: Here's a quick one I just googled:

05 May 2010, 12:19 AM
It looks like the headlights are just a texture. This looks fine when the cars driving along but as soon as it stops from the crash, it looks a bit flat. The headlights should probably break upon impact.

The sky in the background looks kinda strange, the clouds on the horizon look too big. The lighting and reflection on the water doesn't appear to match the clouds. Furthermore, a perfectly straight horizon on land doesn't look right.

I like the way the bonnet buckles like that, I just wander if it could buckle up a bit more. It's hard to find reference for that exact speed but I just imagine with 'crumple zones' and all that, the bonnet would buckle a bit more.

I also have a feeling the entire front of the car would get pushed in causing the front side panels to buckle.

05 May 2010, 04:11 AM
A still rendered in production setting.

05 May 2010, 03:37 PM
It's quite a lot of ground to cover for a light+shade+FX TD reel!

FX-wise as others have mentioned the buckling needs more attention to detail.
Revalis posted some great reference.

Shading: it's great that you're writing your own shaders but it still has to look right. It's not so hard to write a shader (well, in RSL at least, not sure about MR's SL) but it takes some skill to write and lookdev a good car shader. In this case you need to think about the multi-layered nature of car paint; a dark, metallic, very softly reflective base layer topped with a highly shiny and lightly dimpled laquer. The shader has to react to an (HDRI?) environment.
For this camera angle you may not need to think about the metallic flakes or dimples but if you do want to do a closeup you may need to.
Most importantly you don't seem to use a fresnell falloff on your reflections. That is a must!

I don't think you can work much on the lighting until you've nailed the shader.


05 May 2010, 09:52 PM
Thank you all for all your insights. Very helpful!

Different passes output of the shader.

05 May 2010, 11:56 PM
Doodle around the colors of the shader abit
Chose a darker base color. Seem to look better, more metallic. No wonder I chose a very dark blue for my own car.

Original Shader (

New Shader (

New Lacquer Layer (

New Metal Layer (

05 May 2010, 12:52 PM
This makes no sense right now. Ok plausible solution would be, the hand brake slips and the empty car rolls down a hill. But why would there be a rock sitting in the middle of what appears to be an old driveway or path. You could just create a turning in the road here and set up a more substantial rock. It would be far more realistic. Right now it looks badly thought out.

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