Rendering Tip - Use Camera Lights

[Al Hart]

Clearly you seem to be suggesting that everyone has to use your technique otherwise they will end up in prison or on some rendition flight to who knows where.

 

Yes. I think that is the meaning of the word TIP - "My way of the highway". (This sentence is in jest - for those foreigners who cannot recognize sarcasm)

 

I didn't expect such a violent reaction to this tip as I got.

 

I run a Rendering Workshop on another forum, and for the subject one week I gave them a sink and mirror which they were supposed to place in a bathroom and render.

 

Here is a rendering from one of the beginners:

 

 

I don't know if a couple of lights attached to the camera (but not right next to the lens) would help here, but clearly some advice might be good. (It is possible that he achieved just the lighting look he wanted. But since the Workshop was about rendering the sink and mirror, I thought it should have some effects added which effected the sink and mirror)

 

Here was my reply:

 

Hopefully someone will offer some good advice.

 

My "first" advice is to add more lights - probably a ceiling light or 2.

Then, when you get good lighting you should try adding some more reflection. I think you made the bowls reflective - but you should make the countertop reflective as well, and of course, the faucets. It may be that you have already made these reflective,and the highlighting will show up better when you add more lights.

[Al Hart]

what Al is suggesting is a single "flash" from the camera's location.

 

No - I quickly modified the tip to mean "one or more flashes attached to the camera, but separated from the camera by a fixed distance.)

 

SketchUp (which is the modeling package I work with the most) has a feature in the "Film and Stage" plugin has a feature which automatically places a camera component (block/symbol) at the camera location and alignes it with the camera view. If you were to build your camera component with two lights attached, then, after the plugin aligned the camera, the light would easily be used in the scene, and when you went to a new view, amd realigned the camera the lights would come with it.

 

If I get time, I'll try to upload an image with a couple of camera lights added from a couple of views. (The table and chair image was not designed to look good - it was designed to show what the flash would look like in an, otherwise unlit scene)

[Tommy L]

Al,

I cant think of any application for attaching the camera/lights (other than flash). Just because you can, doesnt mean you should.

That said, questioning established beliefs furthers art, so maybe you are onto something, seeing results would answer the issue more conclusively than anything else.

 

Lighting, in 3d, is generally best kept simple and true to life. So you just put lights where there are light sources. The exception to this rule would be additional lighting such as:

1 bounce boards like a photographer would use

2 lights just to enhance highlights/refractions

3 'negative' lights (lights with -# value)

4 ambient light source, such as domelight

 

In the scene your student is creating, he should be encouraged to think about the 3d scene being a real space, consider where the lights would be in real life. The next step (in making it a piece of art, rather than just an emulation) would be to begin composing with light. Ask how light contributes to the scene. What emotional response is he trying to evoke? In 3d, light is everything.

[AJLynn]

In that bathroom scene... if the lights were attached to the camera but located where the bathroom lights ought to go, and the camera didn't move... then the lights could be attached to the camera and be useful.

 

I'd like to give this idea a chance in my mind. Can you post a set of renders done with it that is actually good? The thing is, the idea goes against everything we all know about good lighting, so if you want to show us that it is useful you can't just throw it out there (because the reaction is going to be... what you've already seen). You need to back it up with graphics.

[Al Hart]

With regard to camera lights.

 

Remember this is a tip for people who want to save time or who don't have the skill to illuminate a scene properly.

 

Here is an interior office scene illuminated with mediocre ceiling lights and lighting coming in from the hallway.

 

 

Here is the same scene with two lights attached to the camera - one left and below, one right and above.

 

 

After automatic balancing due to photometrics, the effect is much what you would expect - the foreground is somewhat brighter and the background is somewhat darker.

 

Of course you can balance the camera light effect by raising or lowering the intensity of the camera lights. (Or you can even blend the two images in Photoshop)

 

One reason this is an interesting effect for office furniture dealers is that they tend to layout about 400 workstations, place ceiling lights and perhaps a few task lights, and the want to quickly make images of just a few of the workstations for the clients review. By using lights attached to the camera they can quickly render the workstations desired without having to a

[AJLynn]

No, I don't like that. The first render is not good at all but the second is worse. There's no detail, no materials and no composition but in the first the light has some depth to it, which is completely lost in the second, where it looks like a flash has been used unskillfully. The whole thing looks like something we might have done in undergraduate school in 1999.

 

I don't agree that this is a good techniques to teach beginners. It's counterproductive to teach them anything that's a shortcut that's not a step on the path to learning proper technique.

 

My advice to you would be to read up on real lighting technique, and if you want to get to the level where you can teach it, also study real architectural lighting to get an understanding of how lighting is set up in a building and why it's done the way it is.

[Tommy L]

At the risk of sounding like an *******, Im not sure I like these 'Rendering Tips' posts. You're assuming the position of someone who has a deep knowledge of the subject matter and yet the first two 'Tips' posts have been sub-par advice that could throw off a new-comer to the field.

What you are saying here is: "If you dont know anything about the software, here is a really bad way to light your scenes"

I dont get it.

[HamburgerTrain]

Here's a good article to read why Camera lights are a good thing:

 

http://www.layersmagazine.com/digital-camera-daylight-fill-in-flash.html

 

I'm sure the same thing can be applied to spaces and buildings. But really, we can cheat anyway and dial in any time of the day, however I'm sure it would be useful in some situations.

 

It's not very good at all to completely dismiss an idea.

[amer abidi]

At the risk of sounding like an *******, Im not sure I like these 'Rendering Tips' posts. You're assuming the position of someone who has a deep knowledge of the subject matter and yet the first two 'Tips' posts have been sub-par advice that could throw off a new-comer to the field.

What you are saying here is: "If you dont know anything about the software, here is a really bad way to light your scenes"

I dont get it.

 

Sorry, but i have to agree 100%. Very Misleading.

For good tips, check out sites like Neil Blevins':

 

http://www.neilblevins.com/cg_education/cg_education.htm

Edited November 22, 2009 by amer abidi

[Stephen Thomas]

Al, I think the reason this idea has been met with, I'm going to say skepticism rather than 'violent reaction', is because lighting is such a fundamental part of what we do. And what most of us strive to do is create images that try to convey a certain feeling and invoke an emotional response about the design from the viewer. Lighting is so key to that.

 

The tip you propose sounds more like a screen-grab approach of just being able to see what's in the model rather than creating an image or view with any sort of artistic merit. If that's all clients/designers are looking for then we're all out of a job! Maybe that explains the direction this thread seems to have gone in.

 

I do agree that there is merit in creating default lighting rigs that allow for a quick setup and draft renders to be produced as a starting point. Though I would say this is more suitable for exteriors or product shots. Interiors are a totally different beast and all about the interaction between lighting and materials. As far as the photography analogy is concerned, yes, professionals do light interiors with flashes but I would argue that the placement of these is considered quite carefully in relation to the scene.

Edited November 22, 2009 by stef.thomas

[Al Hart]

Sorry, but i have to agree 100%. Very Misleading.

For good tips, check out sites like Neil Blevins':

 

http://www.neilblevins.com/cg_education/cg_education.htm

 

Thanks - this is a good page. I have been looking around for other peoples rendering tip ideas and this seems to be a very good set of rendering lessons.

[Tommy L]

And also pro photographers use strobes, which are totally different to using a standard flash. Flash is kind of a last resort to getting sufficient available light to produce an image on the sensor (unless you want a dirty, journalistic style). Strobes are more about painting with light.

[AJLynn]

Strobe is a highfalutin' word for flash but the usage is different in "snapshot" photography and good photography.

 

Level 1 (I'm making up this hierarchy but it's useful to show my point): You keep the flash on the camera, as when you're taking photos of your grandkids in full auto mode, hitting the subject with a direct light from the direction of the camera. Any good photographer or visualization artist can tell you many ways in which this can be bad. The effect of the direct light is to flatten the image. The reflections are particularly glaring - on the subject's nose, upper cheeks and forehead, and the eyes (including the "red eye" effect). You might see the person's shadow on objects in the background, which is the equivalent of a 4th wall violation.

 

Level 2: You still have the flash attached to the camera in a fixed position but you take steps to make it less glaring, like putting it on a bracket, bouncing it off a ceiling or bounce card, using a diffuser, etc. This is what the pro photographer you saw at the last wedding you went to was doing with the big metal rig holding the flash pointed backward at a white card over his shoulder. It's as much as you can do in an environment where you need to be mobile and the environment isn't controlled. The negative effects of bad flash are mitigated, but the full creative possibilities are not being realized.

 

Level 3: The scene is prepped ahead of shooting by measuring light, placing lights and flashes, using color gels and in general the lighting setup is controlled and designed by the photographer. This is when they use the word "strobe" to differentiate the practice from snapshot flash photography, which is completely different.

 

If you're paying a pro for a photo shoot in a controlled environment, you expect the level 3 treatment. If the pro flipped up the on camera flash and gave you a snapshot you'd feel ripped off for having paid for it. Kiernan's example is also level 3 - there are one or two off camera fill flashes being used to compensate for the difference in exposure between the guy and his black clothes, and the background, and to make his features stand out. The lighting has been designed.

 

This tip describes a level 1 (or 2 at best) process, when you need to be working at level 3. The camera-attached light is random; your lighting needs to be designed.

 

Those of us on the forum who went to architecture school will understand the importance of unvarnished criticism, so it what I'm going to say here seems blunt you will please understand and forgive. These renders in these tips threads are not good. They are bad rendering. When I taught undergrads, if they had given me work like this I would have docked points and told them to reconsider the lighting. This tutorial is counterproductive and this technique should never be taught to a beginner.

[amer abidi]

This tutorial is counterproductive and this technique should never be taught to a beginner.

 

Nothing personal, but i couldn't agree more!