How to use HDR as indoor light?

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Learning how to use HDR, now can use HDR as an outdoor environment light source. Just wonder how to use HDR indoor (let's say no door and windows)?

If can not, why there are a lot of indoor HDRs provided as shown attached? How to use them?

Additional 2 questions for HDR:

- All HDRs I found are look like Panorama photo, it can be used as environment light, but how to use it as backdrop picture since it looks not normal?

- What is the suitable HDR size to download for DAZ,  4K, 8K, 16K?

Thanks.

Richard Haseltine

The indoor HDRs are intended to be used inplace of a modelled interior, not alongside one. If it is to be used as a backdrop (Draw Dome on in Render Settings) then you will see only a segment of the image (it gets wrapped around te whole scene), so you want the highest resolution possible (unless you know the size of render and the field of view for the renders you intend to use it in, in which case you could work out the minumum size you needed)

mavante

This shows a number of examples that should help:

Iray 102: IBL and HDRI in DAZ Studio

 

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Thank you Richard and Mavante. 

Fishtales said (2 years before) to apply Finite Box, I tried few hours and failed, can not contain the HDR into a room size.

Now I tried 2 ideas for indoor lighting, they all working, report here for everyone's reference:

First I tried Fishtales' second idea, duplicated a ceiling and set it as Iray Emissive under the Surface tab, so the ceiling can become light source to make whole room bright.

Second idea is to 'cut' the house temporarily by Create a New Iray Section Plane Node, and parent a red plane to show where it is, then move it to just in front of the camera to cut the house and let HDR light coming in the house, as shown attached.

They both working fine so that I don't need to set up lights separately.

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Another idea, use this 'Iray Interior Camera': https://www.deviantart.com/heroineadventures/art/Iray-Interior-Camera-V1-3-758604718?comment=1%3A758604718%3A4826903374, produced by HeroineAdventures , similarly as the second idea in my above comment, cutting the house by a script, and cut more,  automatic moving with its camera, works very well.