Create HDRI from image

I have a large background image that I want to turn into an HDRI file. Is that possible?

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Permalink Reply by akinlolu olugboji on August 5, 2011 at 12:40pm

With the Nxt version of AutoCad yes, not sure of other versions.

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Permalink Reply by Render Plus on August 8, 2011 at 9:21pm

Is this a 360 degree panaromic image which you want to turn into a 360 degree HDRi, or is it a flat image.

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Permalink Reply by Paul Davis on August 9, 2011 at 10:51am

It is a 360 panoramic image that is high resolution. I believe it would be perfect for an hdri.

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Permalink Reply by Render Plus on August 14, 2011 at 9:22pm

I looked over on the AutoCAD nXt forum, for hints on this, but I didn't see anything.

Try the Convert Image to HDRi Background button on the Background Tab to convert your image to an HDRI - then try using the image as an HDRi sky (not a Planar HDRi image). (Do not worry about the settings below the button - just use the button to convert the image)

One trick I use when testing this is to render a small item with lots of sky visible to see if the HDRi image behaves as expected.

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Permalink Reply by akinlolu olugboji on August 15, 2011 at 5:21am

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Permalink Reply by Render Plus on August 15, 2011 at 6:31am

The AutoCAD images are probably running the same internal function as our Convert Image to HDRi Background button. Have you tried it with a full 360 degree image?

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Permalink Reply by akinlolu olugboji on August 15, 2011 at 6:35am

No would give it a try if you could just point to where I can get one.

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Permalink Reply by Render Plus on August 15, 2011 at 7:11am

See this article by keith bruns for information on how to create your own HDRi images using a "light probe" and a camera to get a full 360 panoramic image.

http://www.unparent.com/photos_probes.html

(Click on "so, what is HDR?")

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Permalink Reply by akinlolu olugboji on August 15, 2011 at 8:49am

Unless am mistaking, the issues have an image file (jpeg, png tiff etc) and converting to *.hdr format. Now what I need clarifying is, do we have a 360 degrees image?

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Permalink Reply by Rich Hart on August 16, 2011 at 8:36am

Attached is a 360 panorama jpeg photograph that I took at the Golden Gate Bridge in San Francisco, fairly low resolution 2252 x 1261 pixels.

I used the "Convert Image to HDRi Background" button on the Background tab to convert the jpg to an HDRi file.

I then used that as an HDRi background, not a planar background, for a simple rendering of Nancy and a brick box. Here's the result:

I then rotated the HDRi 220 degrees so that you could see part of the bridge, and I get this result:

So the Create HDRi process does work. You just need to get high resolution 360 panoramas that you can use.

Attachments:

SanFran_2.jpg, 2.1 MB

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Permalink Reply by Render Plus on August 16, 2011 at 12:57pm

I would be interesting to turn off the ground plane, and place a reflective sphere in your model just to see if there are problems with reflections which look up (say on a vehicle) and what appears as you look down - although that would usually be obliterated by the ground plane.