If your doing a physics demo (which this was not) then what matters is the code running it and pre rendering would not be a issue.

Err, mmm, context again, physics demos (of game engines) really care about the real time rendering... perfomance penalties are the nightmares of any tech demo of a game engine...

I have been to shader demostration where they show cool things with fractal texture and it is one hundred percent not about rendertime. It was about fractals.

There are things that need to be accomplished first before you start doing engine test.

And people do have deoms on those things in the game industry.

Again my friend, context, shader demo is not equal to a game engine demo, I have been in a couple, and watch online a lot of demo techs, when we talk about games, it has to be real time... physics (Havok, physx) game engines like cryengine2 or unreal engine, all of them are showed in real time because thats how they work... APis like D3D or OpenGL, all of them are realtime...

You can spin it whatever you want, but here, the discusion is about game engines, games, and tech demos, showing the power of the console, that why we keep the topic about the real time...

Edit, you can made a video and show it, but you have to make sure that the tech you are showing can run in real time, unless you want to look like a fool...

Go to GDC you will find everything from business plans to future fractal based shaders and terrain. 

If you think the only thing that goes into a game is the engine you are mistaken.

You are going to extremes by your messure no one cares about things like a hair simulation, they only care wether or not it was rendered in real time.

 Err, again, contex, I never said something like the game engine is the only thing that goes into a game...

Like I said, all the devs that show a game engine or physics engine use real time, to show it to the world...

And again, I'm talking about showing the power of a game engine running in a console or a pc, a tech demo showing how great it is running real time...

I care about the other stuff too, but the my topic doesn't talk about that... please stick with the context... 

What do you mean?

You can go back to read my posts, everything started with the so called tech demo of Crysis, it wasn't a tech demo, then I pointed to the real tech demos made by crytek... NJ5 pointed that it doesn't have to be real time to be a tech demo, and I pointed that if you are going to make a game or show a feature of the game engine, it has to run real time...

Everything I wrote is in the context of game engines - tech demos and real time...

I care, and a lot about other kind of tech demos, but my topic, the thing I disccussed with NJ5 is only about tech demos showed in real time...

^OK then yes if it is said to be a engine demo then it has to be real time.