Second rendering, lighting problem

[dzatto]

Okay, I have a question.
I know my concrete in the foreground is too bright. I can fix that. I also know my guy is floating about 6" above the ground, I can fix that also.

My question is this: Why are my bays so dark? If there's sunlight, it should illuminate the bays like real life. I rendered it with GI turned off, should I have that on? I know that when I was learning to render, turning it on had negative affects on my rendering.

I tried putting lights in the bay (60W 8' lamps, 8 of them) and even double the intensity, but I couldn't see a difference.

Any ideas on how to get the bay illuminated like they would be in real life daylight?

[rdaynard]

Looking at the shadows, I'd say your time of day is somewhere around....noon...? If so, try and earlier time of day (or later depending on the direction of the sun). Other than the things you mentioned, I think it looks pretty good.

[dkoch]

I am no rendering expert, so I will leave suggestions on how to get your bays lit to those who are, but I would point out that unless a significant amount of daylighting is penetrating into the bays, in real life you would not see much in the garage bays, unless you add enough artificial lighting to take the paint off of the vehicles inside. ;-) Most exterior renderings (and photographs) show glazing that does not have a special coating and that is not directly reflecting the exterior scene as black, with the exception of items right at the window, such as window treatments.

[dzatto]

Thanks for the comments guys. My sun is set at 10:00. I was just comparing to actual pictures of a lube center and you can clearly see all the stuff in the bays. It's in shadow but it's not super dark like my rendering shows.

I was thinking about it last night and decided to try and rotate north 45 degrees. Righ now the front is due south, so the sun has no chance of getting in the bays.

I'll post it when I get it looking a bit better.

[dkoch]

In other threads, I have read recommendations to use a "partly cloudy" sun setting, rather than clear sky, to help reduce the intensity differential. But you may already be doing that....

[dzatto]

In other threads, I have read recommendations to use a "partly cloudy" sun setting, rather than clear sky, to help reduce the intensity differential. But you may already be doing that....
Nope! Didn't know I could do that. I'll check into it. Thanks. :beer:

How do you do that, I can't find a setting for different types of skies.

[rdaynard]

To my knowledge you can't change the sky to "partly cloudy". As for rotating the building, have you tried entering the actual coordinates of the site, or the city that it's in? Whenever I do a rendering for a client, I use the site drawings to locate the building correctly, then I change my location to match. Doing this allows me to show the client an accurate picture of what their building will look like at certain times of day. You can change the location within the 'Sun Properties'

[dzatto]

To my knowledge you can't change the sky to "partly cloudy". As for rotating the building, have you tried entering the actual coordinates of the site, or the city that it's in? Whenever I do a rendering for a client, I use the site drawings to locate the building correctly, then I change my location to match. Doing this allows me to show the client an accurate picture of what their building will look like at certain times of day. You can change the location within the 'Sun Properties'
Yeah, that's how I usually do it., and I always draw my sites with bearings so it's true north, not just pointing to the top of the page. This particular site doesn't exist. It's a concept I'm working on, so north is straight up for now.

I just did 2 renderings, one with GI on and one with it off. It looks like that's the problem. With GI on, it lights up the bays a bit more. With it off, it's totally dark.

[dzatto]

Okay, scratch that. It looked great with GI on, but when I tried to do a final render at 300 dpi for an 8.5X11 sheet of paper, it locked up my computer. It was only 1/3 done with the final gather and it was already 3 hours in. It needed to finish that, then render. It woulda took all day long. Not worth it.

[david_peterson]

Dan,
Ever think about setting up a farm, or just letting the thing run overnight?
I've had a single image take over 47hrs to render before. The more lights and shadows you have, the longer it's going to take.

[dzatto]

Dan,
Ever think about setting up a farm, or just letting the thing run overnight?
I've had a single image take over 47hrs to render before. The more lights and shadows you have, the longer it's going to take.
I thought about it, but that's a lot of time for what I need it for. The boss didn't even notice that the bays were dark. I just like my stuff to look as perfect as possible. 4 hour rendering I can handle, 47 hour rendering isn't worth it for what I'm doing. Not yet, anyway. Thanks for the input, though.

That makes me think. Maybe I'll delete the lights I had in the bays, and use GI. They didn't light up anything anyway, but since they are still in the scene, the engine has to figure the lighting for them. Maybe that's why it took so long? I'll check into it and try again. :beer:

[david_peterson]

There's a solid chance that the additional light were the problem. You also want to be sure that your model is as close to 0,0,0 as you can get it. Bad things will happen otherwise. If you still aren't getting what you want, you could try to place a second sun or something more like a "natural" light source inside the bay.
They rendering that took 47 hrs was a night shot for a 5 story building with a about 75 light sources inside the building casting light across the grass, trees and parking lot. Came out great, but I had to wait and let it grind for the entire weekend.

[dzatto]

Okay, that was it. This time the entire rendering took 3.5 hours. Much better. I deleted the extra lights and the bay is brighter with the GI turned on. I also rotated the north direction a little to get better shadows. Here's the final product. It looks weird unless you zoom in on it to see the detail. I guess that's because it's 300 dpi. It doesn't print like that, though.

[dkoch]

Well, now that it is perfect, I will offer congratulations on a very nice rendering. I think the service bays show quite nicely. My only, very minor quibble would be that the shadow on the guy out front does not seem to be correct, assuming that both of his feet are on the ground plane.

I have always wanted to have the time to try to learn rendering, but I never seem to be able to find it. Maybe when I retire in twenty or thirty years.... :lol:

[dzatto]

Well, now that it is perfect, I will offer congratulations on a very nice rendering. I think the service bays show quite nicely. My only, very minor quibble would be that the shadow on the guy out front does not seem to be correct, assuming that both of his feet are on the ground plane.

I have always wanted to have the time to try to learn rendering, but I never seem to be able to find it. Maybe when I retire in twenty or thirty years.... :lol:
I agree 100%. As a matter of fact, in my first post I mentioned that he was floating. I thought I put him in the scene at the wrong elevation, but he is at the same elevation as the concrete he's walking on. I think there's a problem with the actual RPC I used. He also looks a tad short to me.

[duguid]

I have similar problems lighting up interiors, what is this "GI" that you keep talking about?
I'm doing a lot of renders with large grocery stores, and while its not probably realistic, my clients usually like to see the large shopping space lit up, even on shots in the middle of the day. The problem becomes lighting spaces that have area's of 75,000+ sq. ft and with exposed ceilings of 25'+ high, with the minimum amount of lights to keep the render time down. As it is now, I need to have lights with wattages of around 15,000 in order to get the desired effect, but it still tends to light somewhat unevenly. If anyone has any advice, let me know. I've never fully understood the daylight portal options, maybe that's something to explore.

[david_peterson]

Hi Steven,
If you want that type of realism you really need to just add the 100 or so 150w overhead lights that would be in that space.
What kind of results are you getting now. You should post an image for all to see :lol:.

[duguid]

Here's the rendering, had to cover up some signage. Best setting, 25 lights on, 5700x2600 resolution. Took 3 days on a dual-core 3.2gHz, 3.5 gigs of RAM machine.

What is GI?

I also has the problem that if I used ceiling lights at the deck, the ceiling would be dark. Used a modified hanging strip light to cast light up and down. Turned on about every 4th light.

*edit* Just realized I'm in the ACA forum, and this is a Revit render. Sorry, did a post search to get here in the 1st place and thought I had it narrowed to Revit forums. Sorry to use up your guys' time.

[david_peterson]

I believe the GI in question here is the Global Illumination settings.
Image looks nice. 3 days though. Have you ever thought about setting up a farm?