HELP! my scene is still rendering nothing but black.

[lo]

that's very vague. You need to give much more information than that, what render engine, render settings, what your scene consists of, etc.

[vallaha]

ok i have a sphere with hdri on it. my model is high polygon(slow rendering. how can i speed it up?) ive fliped my normals so they are pointing in the right direction. so why is it rendering dark? using MR renderer.

cheers for helping

[lo]

hdri environment is indirect illumination, meaning you need to turn on final gather to render it.

[vallaha]

i have turned on FG in render set up but still no luck. any other ideas?

[lo]

post a screenshot of your settings or the scene

[vallaha]

ok. pic on left is my viewport, iv doine some tweaking so im now getting something in the render window, thats all. its dark but not pitch black as io had it before

[lo]

oh, I understand your setup now. What shader are you using on that sphere?

[vallaha]

just a phong

[lo]

well that's probably your problem. You need something that outputs light. Haven't used mental ray in a while but the self illumination options of the Arch&Design material can do this.

[JeffPatton]

See if #10, #16, here: http://jeffpatton.net/forum/index.php/topic,4.0.html and this discussion: http://jeffpatton.net/forum/index.php/topic,32.0.html can help.

[vallaha]

but the hdri should automatic give light

[lo]

when used properly. Read the links that Jeff gave you and follow those instructions, it's not that complicated.

[vallaha]

sorry im lost. the only question and answer that seems most likely is question no. 10 (please see below) but this, i think refers to LDR images, im using an HDRI and i dont know where to
access mr Photographic exposure's Physical Scale settings. i have tried finding them but i think their hidden somewhere. again im just using mr render engine and a hdri on a sphere.

can someone be more specific? cheers

question
10. My background/environment map isn't there/renders black:

answer
Most of the time this is an energy/exposure issue. Think of it like this, if you went outside and took a photo of the sky and then printed it out onto paper & held that printed sky up to the real sky which would be brighter? The real sun & sky of course would be brighter than a print out of the sun/sky.

That's what is happening when you put a LDR (low dynamic range) image into your background and have the exposure configured for a daylight scenario. The LDR (.jpg, .png, etc.) photo of the clouds or sky doesn't have enough energy to be visible with an exposure setup that's configured for daylight.

So how do you make it work? Well there are a couple of ways:
A. You could modify your mr Photographic exposure's Physical Scale setting. For example, on the photographic exposure control you can use the "unitless" physical scale with a value of something like 80,000 or so.
B. You could increase the "Output Amount" on your environment map until it's visible. You may also have to increase the "RGB Level"..depends on your exposure settings & the bitmap.
C. You could wrap your environment map inside the "Utility Gamma & Gain (mi)" shader and adjust the "Gain (multiplier)" to make the image brighter.
D. In 3ds Max 2010 you can disable the "Process Background and Environment Maps" exposure option.

[vallaha]

well that's probably your problem. You need something that outputs light. Haven't used mental ray in a while but the self illumination options of the Arch&Design material can do this.
what am i thinking. im using an hdri image to light the scene not a phong and my self illumination is 100% and its still dark. those links weren't much good either. help?

[lo]

this is what your sphere material self-illumination rollout should look like

[JeffPatton]

You're attempting to light a scene with a self-illuminated material applied to a dome. There are several problems/drawbacks (like blocking light and/or FG if not configured properly) with using domes to light a scene and IMHO there's really no need to use a dome for illumination these days. Which is why I pointed you to point #16 in my FAQ:

"16. How do I illuminate a scene with an .HDR image when using 3ds Max & mental ray?
Answer: There are several ways some are:
A. Create a skylight. Assign your .hdr map to the skylight. Enable Final Gather & render.
B. Create a skylight & configure it to look at the scene environment. Assign your .hdr map to the scene environment. Enable Final Gather & render.
C. Use the HDR map as a self-illuminated material & enable FG.
ETC.

Now, of course you'll have to pay attention to things like using the proper mapping coordinates & exposure settings when setting up your .hdr map. You may also want to use a small, blurred version of your HDR for illumination as it will require less FG samples to produce a clean render. You should be able to find plenty of data on HDR's with a thread search."

With that info in mind: delete your dome, create a skylight and either assign your HDR to the skylight's map or configure the skylight to use the scene environment for it's color. Then make sure FG is enabled.

Now, another issue you'll need to address is exposure. From the screen shot you've attached it appears as though you're also using the daylight system? If so, it's VERY powerful & by default your HDR is not. You're going to need to adjust your exposure settings or the HDR energy before it will be visible. And that's why I provided a link to #10 in my FAQ:

"10. My background/environment map isn't there/renders black:
Most of the time this is an energy/exposure issue. Think of it like this, if you went outside and took a photo of the sky and then printed it out onto paper & held that printed sky up to the real sky which would be brighter? The real sun & sky of course would be brighter than a print out of the sun/sky.

That's what is happening when you put a LDR (low dynamic range) image into your background and have the exposure configured for a daylight scenario. The LDR (.jpg, .png, etc.) photo of the clouds or sky doesn't have enough energy to be visible with an exposure setup that's configured for daylight.

So how do you make it work? Well there are a couple of ways:
A. You could modify your mr Photographic exposure's Physical Scale setting. For example, on the photographic exposure control you can use the "unitless" physical scale with a value of something like 80,000 or so.
B. You could increase the "Output Amount" on your environment map until it's visible. You may also have to increase the "RGB Level"..depends on your exposure settings & the bitmap.
C. You could wrap your environment map inside the "Utility Gamma & Gain (mi)" shader and adjust the "Gain (multiplier)" to make the image brighter.
D. In 3ds Max 2010 you can disable the "Process Background and Environment Maps" exposure option.

For more detailed info, see this:http://mentalraytips.blogspot.com/2008/02/why-does-mental-ray-render-my.html

Note: In 3ds Max 2010 the "Process Background and Environment Maps" exposure option now works with the photographic exposure control."

In that info I've provided some very specific things to adjust, however you said:
sorry im lost. the only question and answer that seems most likely is question no. 10 (please see below) but this, i think refers to LDR images, im using an HDRI and i dont know where to access mr Photographic exposure's Physical Scale settings. i have tried finding them but i think their hidden somewhere. again im just using mr render engine and a hdri on a sphere.

While I mention LDR images in that post, it's not specific to LDR images. It's valid for anything you use to try and illuminate a scene with while also using the photographic exposure control.

You mentioned that you don't know where to find the physical scale settings in the photographic exposure control. For that I'll refer you to the 3ds Max help file (F1) because it's already explained there in the info on the mr photographic exposure control.

So in conclusion, in it's simplest form to light a mental ray scene with a HDR in 3ds Max all you need to do is apply your hdr to the scene environment, add a skylight & enable FG. It becomes a bit more complicated when you add in the daylight system & exposure control to the mix because you have to balance the exposure control for a very strong light source and a relatively weak (by default) HDR light source. That's why you need to either adjust the strength of the HDR or the physical scale settings on the mr photographic exposure control.

[vallaha]

you wrote,

Now, another issue you'll need to address is exposure. From the screen shot you've attached it appears as though you're also using the daylight system? If so, it's VERY powerful & by default your HDR is not. You're going to need to adjust your exposure settings or the HDR energy before it will be visible. And that's why I provided a link to #10 in my FAQ:


i dont know if im using the daylight system? the only thing i know is i have an hdri mapped to a sphere. i have used the same settings on this sphere with other renders and with good results. but not for this render of a spaceship. i do have fg checked on. in materials editor i do have the self illumination cranked up to 100.

[vallaha]

sorry for being a pain but i did what you said,

A. Create a skylight. Assign your .hdr map to the skylight. Enable Final Gather & render.

but i still get the same thing. please see attached file

cheers

[JeffPatton]

I think we may have went though all of this for one little check box...

Why did you enable the "Draft Mode (No Precalculations) option enabled in your FG settings? It's off by default so you had to enable it. At any rate, once you turn that off I believe it should render as expected.

[vallaha]

cheers but it dont work. this is what i get in the attched file. the same as before.

[JeffPatton]

Hmmm, well then there are other issues to address in the scene somewhere. What are they? I have no solid idea because you've only provided random bits of information on your scene. I have a hunch that you still have an exposure conflict. I say this because it still looks to me like you have the mr physical sky for the environment instead of a HDR.

If that's the case then since I can see the physical sky without it being blown out (super bright) that means the photographic exposure control is set at the default value of ev15 for a daylight scene. Which in turn means your HDR (mapped to a skylight?) is not bright enough to illuminate the scene. But again, I'm just drawing straws here because you haven't posted a screen shot of your environment/exposure settings.

I've mentioned the exposure issue before but you said something like you don't know where the exposure control is or something along those lines. My response to that was it's explained in the help file, that reply still applies. Hit the F1 key while 3ds Max is running and look up the mr photographic exposure control for detailed info on where it is, how to use it, etc..

There are sample HDR scene on the internet, sample HDR scene on the bonus DVD that ships with 3ds Max 2010, video tutorials on the process, etc...but if I'm being honest here, looking at sample scenes won't really help you in the long run if you don't know how to use/adjust features like the exposure control.

I strongly urge you to go through the rendering tutorials that ship with 3ds Max because you'll gain an understanding of the features like the mr photographic exposure control & the daylight system that in turn will help you understand what's going on with your scene and assist you later down the road as well.

[vallaha]

ok cheers ill give it a good go in the morning

[vallaha]

ive done some fiddling and i think weve done it. eccept for an horizontal streak at the top of render window?

[JeffPatton]

ive done some fiddling and i think weve done it. eccept for an horizontal streak at the top of render window?See point 10b in my FAQ: http://jeffpatton.net/forum/index.php/topic,4.0.html

[vallaha]

cheers its all working fine now. you were a great help

[vallaha]

i wouldnt mind my light animated so as it moves with my camera. ive tried linking but it dont work.

[lo]

select the daylight system object, go to the motion panel (4th button from the left on the command panel), and switch your daylight system control from 'day, time and location' to 'manual'. After this linking your light to the camera should work properly.

[vallaha]

i do as you said and it works but my angle of light changes from the left pic to the right and i cant manipulate the light with the gizmo to get the original angle of light i want that is the left pic.

[lo]

ah, it might be because you're using a target camera? Not sure.

It would be easier to return the daylight system to 'day, time and location' mode and instead link the compass object to the camera. That is guaranteed to work.

[vallaha]

i am using a free light and theres no compass object in my scene

[lo]

I don't see how that's possible unless you have deleted it.

[vallaha]

of course your right, i just dragged out another light. what was i thinking? but now my render i s dark again. i think its got something to do with that arrow on end of light

[lo]

an arrow would mean you're using a max standard sun and not an mr Sun. make sure your daylight settings are mr Sun and mr Sky.

[vallaha]

cheers its working now

[vallaha]

my rendering was going so well then all of a sudden my whole geometry turned red as did my renders?

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