How to use HDRI in VfR

[puha0941]

Hello all!

What would be the best way to use HDRI for VfR?

As far as my research went, the best way is to use dome light and to put it as a texture in the dome light. When I do this, I should turn off GI and Background in the vray options, right?

Is this method better than putting them HDRI into GI and Background in the vray options?
Could someone walk me through the right workflow?

Thank you!

[puha0941]

I tried using HDRI on Dome light. And even if I crack the texture resolution up, (from 512 to really high) the final result in the render is pixellated...
Could someone tell me why this is happening and how to fit it to get a sharp image?

Hello all!

What would be the best way to use HDRI for VfR?

As far as my research went, the best way is to use dome light and to put it as a texture in the dome light. When I do this, I should turn off GI and Background in the vray options, right?

Is this method better than putting them HDRI into GI and Background in the vray options?
Could someone walk me through the right workflow?

Thank you!

[fooprobe]

Can you post the "pixelated" render? Usually for environment lighting you actually want lower res and blurry images (check out HDRLabs SiBL page for samples) because more res leads to blotchy renders, which you have to fix by increasing IR/LC values = slow. I don't think you need an image bigger than 1000x500, though I'm sure others will disagree.

From what I can gather, dome light produces better/sharper shadows with a given HDR than GI skylight, at the expense of speed. If you are doing renders of objects or products where shadows would be noticeable, then it is preferred. If you are doing a building exterior or interior then I personally don't see the point, as the sharpness of the shadows from the environment light won't usually be that noticeable, and I prefer the speed of GI skylight.

Background is totally different. First, you don't need HDR unless you are rendering to HDR/Exr and playing with exposure in post. Second, you need very high res, usually 8000x4000 for renders in the 1000px wide range, and bigger for bigger render size. This is because only a small portion of the total image is visible in the render, and if that portion is too low res you will see the pixels.

[puha0941]

Thanks kindly, for your reply!

Your last point on the size of HDR that is in the background showing up small or big depending on resolution is mind-blowing! I am learning something new.
So you are saying, to get more of the HDRI sky in the background as a render, I need to render big size, right? If I render the same scene with lower res 1000px then, the portion of the sky will be smaller than the high res and therefore will pixellate.

Thank you for the tip I will test them as well.
[QUOTE=fooprobe;574422]Can you post the "pixelated" render? Usually for environment lighting you actually want lower res and blurry images (check out HDRLabs SiBL page for samples) because more res leads to blotchy renders, which you have to fix by increasing IR/LC values = slow. I don't think you need an image bigger than 1000x500, though I'm sure others will disagree.

From what I can gather, dome light produces better/sharper shadows with a given HDR than GI skylight, at the expense of speed. If you are doing renders of objects or products where shadows would be noticeable, then it is preferred. If you are doing a building exterior or interior then I personally don't see the point, as the sharpness of the shadows from the environment light won't usually be that noticeable, and I prefer the speed of GI skylight.

Background is totally different. First, you don't need HDR unless you are rendering to HDR/Exr and playing with exposure in post. Second, you need very high res, usually 8000x4000 for renders in the 1000px wide range, and bigger for bigger render size. This is because only a small portion of the total image is visible in the render, and if that portion is too low res you will see the pixels.

By the way, how do I post images on this forum?

[puha0941]

Dear fooprobe,

Just tested a scene with a hdri in the background and gi slots with physical camera.

Rendered two scences: one with low (800xp wide) and one with high (10000 px wide)
And it looks good!

Can you post the "pixelated" render? Usually for environment lighting you actually want lower res and blurry images (check out HDRLabs SiBL page for samples) because more res leads to blotchy renders, which you have to fix by increasing IR/LC values = slow. I don't think you need an image bigger than 1000x500, though I'm sure others will disagree.

From what I can gather, dome light produces better/sharper shadows with a given HDR than GI skylight, at the expense of speed. If you are doing renders of objects or products where shadows would be noticeable, then it is preferred. If you are doing a building exterior or interior then I personally don't see the point, as the sharpness of the shadows from the environment light won't usually be that noticeable, and I prefer the speed of GI skylight.

Background is totally different. First, you don't need HDR unless you are rendering to HDR/Exr and playing with exposure in post. Second, you need very high res, usually 8000x4000 for renders in the 1000px wide range, and bigger for bigger render size. This is because only a small portion of the total image is visible in the render, and if that portion is too low res you will see the pixels.

[fooprobe]

Glad it's working better for you. When you post a comment there is a little tree icon above the text window you can use to upload a picture.

On the background, maybe I wasn't so clear. The render output size doesn't change how much of the background you will see. It will stay the same - the only way to change that is with lens length, which changes the view angle.

My point was that for a given lens length (view angle) you will see only a certain percentage of the background image. Lets say you use an 8000x4000 image and your view angle is about 90 degrees. You will have one quarter of the background visible in the render, so you get 2000 pixels of background image resolution (However that 2000 px is spread over a sphere in the background, so I'm oversimplifying, but it's close enough). If your render output is about 2000 px wide or less then this will be ok. If your output is noticeably bigger (let's say you want to print the render large, for instance) then you are spreading that 2000 pixels across a greater area and will start to notice the background getting blurry or pixelated.

[puha0941]

This is very clear. Thank you fooprobe!

Glad it's working better for you. When you post a moment there is a little tree icon above the text window you can use to upload a picture.

On the background, maybe I wasn't so clear. The render output size doesn't change how much of the background you will see. It will stay the same - the only way to change that is with lens length, which changes the view angle.

My point was that for a given lens length (view angle) you will see only a certain percentage of the background image. Lets say you use an 8000x4000 image and your view angle is about 90 degrees. You will have one quarter of the background visible in the render, so you get 2000 pixels of background image resolution (However that 2000 px is spread over a sphere in the background, so I'm oversimplifying, but it's close enough). If your render output is about 2000 px wide or less then this will be ok. If your output is noticeably bigger (let's say you want to print the render large, for instance) then you are spreading that 2000 pixels across a greater area and will start to notice the background getting blurry or pixelated.