Hilight question: coming off object?

[pgregory]

I think the effect you are describing is a type of lens flare. It is not actually the highlight itself that is 'away' from the object, just the way the intense brightness affects the lens, beit a camera, or your eye.

You don't mention which software you are using, but most packages support lens flare effects to some degree, take a look through the manuals for lens flare and you should find something.

HTH

Cheers

PaulG

[Christoff]

I understand that the lens flare effect gets that effect from light sources, does it work on objects like im describing in 3ds max? one example of what i am talking about by an object 'glowing' in very lighted areas is at
http://www.antropus.com/senzaazione/pics/velha4.jpg
look along the left side of her face to se what i am talking about. thanks! :)

[lazzhar]

for the picture you posted I bet it's not done in a 3d package.
In a program like Photoshop select the bright area in your rendered image and create a layer from it then blur it and change th emode to something like screen ot color dodge will give you the same effect without the cost of waiting a 3d renderer till finishing.
Try it it's better and most of professionals work in this way.
Good luck.

[Christoff]

the picture i posted is a still from a 3d animation that was on the front page of cgtalk.

[lazzhar]

The same technnique could be used in a compostiting program like Combustion, After FX, Shake, DFusion...etc

[Christoff]

so it would most definately not be a 3d application based effect?

[lazzhar]

As mentioned it's a lens effect. It has been implemented to simulated the real lens effect in the cameras.
Most 3d packages can do it, but it's basecly done after the rendering, so it's post process. Therefore why leave the 3d program do it for me if I could do it by myslef quickly?
Imagine if you are rendering a picture like the one of antropus, and you need to increase the glow effect, would you rerender the picture again and again just to see the results? no it's wasting time this way.
Just render the clean picture then post processing would be the suitable solution, especialy if you're working in production.

[Christoff]

thanks alot lazzhar that helps. this makes me reconsider how some of the things that i have seen on this site are done. i guess i need to familiarize myself on post-production!

[NanoGator]

I might be able to provide a little insight here.

In the CG example you showed us, imagine you are photographing a real person that looks like that. In order to achieve the flare (in CG terms, it's usually called a bloom, you might be able to find a plugin that does that) you'd need a diffuse filter on the camera. The way it works is when the light passes through the filter, it is sent off in every direction, causing it to get a little fuzzy.

There is a very simple way to achieve this using a normally rendered image and Photoshop.

- Load your base image and duplicate it into a new layer called "diffused"

- Select the diffused layer, and go to image/adjust/levels. This'll bring up the levels tool. Take the left slider and move it towards the right. What you'll see is the dark areas of the image get darker and darker. When you arrive at a point where you mostly just see the highlights, hit Okay/Apply.

- Go to Filter/Blur/Gaussian blur. The size of the blur will affect how big the bloom is. The radius of the blur is dependent on the resolution of the image. Try 60 to start with. It's a little high, don't worry, this is just an experiment.

- It'll be dark, don't worry. We'll fix that. Go to the transparency mode on the diffuse layer, and set it from normal to screen. What this does is it sort of adds the top image to the bottom image. It's not exactly additive, though. It works the same way as taking two projectors and projecting two images on the same screen. You can imagine how they'd get brighter? If you were to take a red layer, green layer, and blue layer and add them all together using screen, you'd get white. Just like in real life.

- You may or may not notice much of a change here. The blur really darkened the diffuse layer. No problem, use your levels tool again. Image/Adjust/Levels and take the right slider and move it towards the left. If you watch the preview, you'll notice the bloom getting more and more intense as you move it towards the left. Let go when you've hit a level you like.

- For added fun, you can use color balance on this layer and adjust the color you want.

This is the simple way of adding a diffuse glow (bloom) to your image, and you have total real-time control over it. It's also reasonably accurate. I've used plugins for creating bloom and I've never been very happy with them. Either they're slow or they're not so easy to adjust. You get used to that real time feedback.

If you found this interesting, check out my thread here:

http://www.cgtalk.com/showthread.php?s=&threadid=93031

Now technically this is a Lightwave thread, however it does contain a sample file you may find interesting. The LW file I included also has a Photoshop 7 file with a post-processed image I made in multiple layers. One of the layers is there to simulate a form of bloom. Though it was meant to simulate an underwater scene, I think you'll find it relevant to your question.

If you have any questions, let me know. I've done this type of effect quite a few times and have solved a few problems associated with it.

Cheers.

[Christoff]

wow that helps alot. its good to see an example of what someone is trying to tell me so i know we're on the same page. now, i'm pretty new to post-effects. are they applied often? do most of the images i see on cgtalk have some sort or another kind of post-effect applied to them? do most compositing applications have these capabilities for animations?

[lazzhar]

Most of scens are rendered seperatly in many layers, at least you should render your character alone and its envirement seprated. then compose in a composting program.
Not all pictures need to be processed after rendered, but sometimes you need some color corrections, or adding some lens effects like glow, lens flare and so. Some prefer adding Depth Of Field in this stage too.
I bet you have to get into post-processing one day or another.
good luck.

[Christoff]

well thanks alot to you guys! i really appreciate it. and NanoGator i really found that file that you put up to download on your other thread to be helpful. thanks alot!

Lates.

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