Glow reflection

[Jackdeth]

Just render out that relfection with all objects black other than the one that you want to glow, and to do that you just make that object visible only in relfections. Use that matte for a post 2d glow.

[twistedpoly]

Jackdeth thanks for reply

your idea would work, but not in my case. Imagine a car driving on wet road and you are watching it almost from the ground. I need to get those "stripe" kind of reflections, not the same glow that i can see on the object.

any other ideas?

[twistedpoly]

this (http://www.autobytel.com/images/carPics/TestDrv/Lyons/NSX/wet-look_650.jpg) is what i would like to achieve

[Pete2003]

Can you not achieve the effect in post? Imagine you have a complete reflection pass (You could do this also setting the pivot point on the road and by scaling the car -1 in the y axis, in effect having it drive on the reverse of the road).

Composite this reflection pass in your scene in your compositing software of choice :)

Okay, so now your road looks like a mirror, I notice in the example you showed that only the brightest areas get reflected. So, you just need to 'knockout' the darker areas of your reflection (cant think of exactly how this is done off the top of my head, but im sure its quite simple), apply a blur, apply a glow, then maybe 'screen' the reflection in your composite.

Im not positive this will work but hopefully it will give you some ideas :)

Pete.

[twistedpoly]

Pete2003 thanks for that post but....this doesn't work either. :) Forget about blured reflections and reflections of the car. Only thing that i need to know is how to make similar car headlight reflection on the asphalt as shown in the picture.

..got to figure out something...

[mverta]

What do you mean "forget about blurred reflections"? THOSE ARE BLURRED REFLECTIONS; specifically, anisotropic blurred reflections as seen here:

Blurred Reflection (http://www.neilblevins.com/cg_education/aniso_ref/aniso_ref.htm)

You can do it with reflectionUtility by Horvath Szabolcs, quickly, or use a DGS shader, and spend the rest of eternity waiting for the render to finish. (You'd have to set the samples up so high to get a decent look it would be ridiculous).

_Mike

[sundialsvc4]

I share the opion that "it most definitely would work 'in post,' and that is exactly the way that you should do it." :wise:

Referring to your example-image, you would render the car as one strip; and you would render the asphalt and surrounds as another; and as a third and entirely separate strip entirely, you would render the reflection. This would be a perfectly-black (transparent) strip of film containing only the shiny reflection of the headlamps that you see on the pavement... but no pavement and no car. You can do this very simply with just a couple of lamps positioned where the headlights are. The process that you use to make the car's headlights appear to glow will have nothing to do with the process that creates the reflections on the pavement.

These so-called "beauty passes" are often used for reflections, lens flares (ick...), foggy-night effects of any sort, and specular effects like these headlights. It is much simpler for the computer, and gives you much more control in the production process, to keep the generation of these different channels of information entirely separate from one another. If you try to do it all in one gigantic render, the computer will be grinding away, perhaps literally for weeks, trying to make sense of all that bouncing light. {And your manager/client won't quite like it, of course, and will suggest "just a few simple changes," and then he'll wonder why you're going :cry: and :banghead: and telling him he'll have to wait another week to see results!)

[playmesumch00ns]

I doubt you'll be able to get something convincing in post if the car's going to move. I'd either do it with anisotropic reflections, or a cheaper way would be to put a very fine-scale bump on the road surface and put some specular point lights where the car's headlights are.

[anthonymcgrath]

yeah in my current anim I've done a seperate ref pass of the road surface using other objects as cutout shapes on the renderpass. i'm using blurred reflections in my mental ray rendering options and then I just comp it in later. it works and you can do exactly the same thing with another pass of the headlamps reflections then add the glow in afterward.

dont just try and do it in as few layers as possible - comp man comp!! its much more flexible and gives more flexible results afterward.. if you need a dozen rendered layers per shot so what?! thats nowt compared to some high end scenes!

heres my current wip - dont know if the link still works but should give an idea - its still quite rough tho..
http://www.savefile.com/projects/117903

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