My Rendering comes out solid black.

Bootwink

I was making some good reders in Iray, open up to do another Render, but now there if no image just a black image! I chacked there is nothing in front of the camera to block the light. I know I did somethng wrong. I haven't renderd in Iray that much. there is obviously I did something wrong. 

Richard Haseltine

Is the camera below ground level?

kenshaw011267

Chek that the camera lens is not in/behind something. I've had situations where the viewport showed everything fine but the render was black and solved it by moving the camera out of the object.

Bootwink

That was the first thing I thought of, That wasn't it. One thing I did to see if I could figure out what was causing this. I had a scene with a cow a dragon and some and a lamb, that rendered  fine. Then I added a barn that had ground attached looking at the scene through the camera I could see every thing fine but a lot of times when I add ground. I get a pure black render, with no detail. I  spent a whole day trying to get the picture correct for a good render. I saved the Pic till I figure this out. So that I know what I'm doing wrong. Today I had a  few monkeys on the ground Tendered then with nothing else.  then I put  grass down it rendered, but I never could get the pic light enought. it had good color, but no matter what I did I couldn't get it near light enough. I tried just about every type of lighting I have allway comming out in not the correct brightness I wanted. I am doing something wrong. 

kenshaw011267

You could add a distant light with the lumens cranked up high (1.5M or the like) or mess with the tone mapping (increasing the exposure will make a brighter image).

Bootwink

Iray has Beautiful Renders, But the way you use it is not logical to work with, to me anyway. you put a few people in a scene and see where every things stand. OK you ad a light without any adjustments and then render to see what needs to be adjusted, nowing there will be adjustments. but then with a added light the natural thought is it will be brighter but its darker.I crank up the intensity and the renders sometimes get brighter,and sometimes not. I"m going to have to spend a day so how you use it makes since. I need to know what every does. I know it's me and Iray. but I never had in other program not make sence, at this point.  I know it does a beautyful job. LIke when I add some grass and render, it gets darker instead of brighter. I know there will be adjustments but get darker? 

kenshaw011267

You need to check the settings in the camera and render tab for the headlamp. It is set by default to be on when there are no other lights, that DS recognizes as lights, in the scene. By adding a light you disable the headlamp and that is probably way too little light. 

JonnyRay

Also, make sure nothing you loaded added a physical skydome. These upside down half-spheres were used for adding skies to renders in the past (and still work well for 3Delight renders). However in Iray they will block your environmental light. To iray you just inverted a huge bowl over your scene which will block any HDRI lights or distant lights you've added to the scene.

Bootwink

Those Are all good ideas to know, I'll see how that works. this makes a structured sents of way I wan't aware. Thanks, I know I will goof up. as this still new, I had no starting point to understand the way you start a rendering, under way the lighting had to be assembled to under stand what your trying to do. again Thanks very instructive.

JD_Mortal

Sometimes the "getting darker", is just an optical illusion.

Things seem brighter when against a black background, than when they are surrounded by brighter things. (Not saying that is the case here, but it may be part of the issue.) This is the same illusion as the moon seeming "bigger", when it is on the horizon. as opposed to when it is up in the middle of an empty sky. Because you can compare it to the surrounding objects on the horizon, instead of the nothingness of black space.

Things can also have this happen if you have added an older model that has a "Dome", and lighting, intended for the 3DeLight engine, not the IRAY engine. Thus, you are blocking the "sun" or "lighting sky", and only seeing the dim lights that were intended to be for 3DeLight. (The lighting values are nowhere near being correct between rendering versions. Using 3DeLight lights, if they even work, will be a LOT darker. Like 60,000 lumens darker.)

Things can also get darker BECAUSE you added the grass, blocking the light that was once coming UP from under the model, if you use the "HDR lighting". That dome emits light around the full perimiter of the sphere, casting it up onto the model. Adding the grass, and a physical ground, as opposed to the fake ground option in the render-settings, will block that lighting from below. (Though it should not be that dark.)

Also, if you have the option to AUTO use camera-light or "Dome and scene", or "Scene only", and you now add lights, it will alter the lighting in odd ways. (I suggest turning the camera lighting off, since it is not well controlled or functional in the default position and lighting-values.)

Another thing to remember is that the auto-lighting adjustments in IRAY can be odd at times. The photometrics calcualtions can be disrupted by certain shaders and materials and even objects, which can throw-off the "best guess", that auto has to offer. For those rare instances, you are better-off learning how to use the camera settings, or just manually adjusting the scene lighting values with the most obvious values that you do know. (Ignoring things like ISO values and F-Stop, etc...)