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Rendering HDR
Posted: 14 February 2013 02:13 AM   [ Ignore ]
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Hi all:)

I’ve been trying to make an HDR render to be used as background and IBL in Carrara - after what seems to be a reasonable time for the render, all I get is either a pure black or black with stripes image - I use HDR View to see the HDR.

I’ve tried with the 360 panoramic view as well as perspective projection, with the same result.

My process is to set the document size - ideally this would be 8000 X 400, but any size gives the same non-result.  Then select either panoramic or 360, then render to disc.  I’m testing on preset scenes, so have not made any camera or lighting adjustments.

Are there perhaps other settings that must be dealt with to get a result?

On some related issues - if I set a reasonably largish document size, the controls on the right of the screen are overridden, so can’t pan and zoom.

Also noticed that the option to save as HDR probe is greyed out - this isn’t used in Carrara, but is it not the type of HDR that is used in Bryce for IBL?

Any assistance will be greatly appreciated:)

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Posted: 14 February 2013 03:32 AM   [ Ignore ]   [ # 1 ]
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Horo has put together a series of tutorials to help with this very topic and they are provided as part of the free content with Bryce 7.1 Pro.  Unfortunately it’s not always that easy to find out where your free content is… so, Horo again, has made this little PDF to explain that too.  So if you have not already done so, look at Horo’s HDRI creation tutorials.  And if you can’t find them look at this PDF.  Bryce Content PDF by Horo

He is the Bryce HDRI master, and he will probably spot this post when he next visits the site and provide more fulsome answers, but until then, I recommend the tutorials as they will at least help you understand the nature of the problem better.  Oh, as for the size of the image, there is a limitation, beyond 3840 pixel diameter you might run into bugs.  That much I know, Horo will know more.

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Posted: 14 February 2013 09:16 AM   [ Ignore ]   [ # 2 ]
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Thank you, David - with your help I have found the hidden content and taken a look at Horo’s very interesting and in-depth tutorials:)

What I am probably looking for is the mirror ball method?

I did observe that he refers to Bryce 6.1 and nowhere that I read did he mention using the HDR render function - is this function new to Bryce 7 and I am possibly looking at an old tutorial?

In any case, I will follow the tut and see where that gets me.  In fact, there are so many more Bryce tutorials than what are available for Carrara, especially for landscapes, that I think I must now buckle down and do try doing all my landscapes in Bryce:)

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Posted: 14 February 2013 10:08 AM   [ Ignore ]   [ # 3 ]
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Perhaps try to use ‘render’ instead of ‘render to disc’

As soon as you’ve done a regular render, use the export image option in the file menu.
Choose ‘HDR Image files’ option.

Then you will get an HDR image of exactly what you see in the viewport.

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Posted: 14 February 2013 10:58 AM   [ Ignore ]   [ # 4 ]
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Roygee - 14 February 2013 09:16 AM

Thank you, David - with your help I have found the hidden content and taken a look at Horo’s very interesting and in-depth tutorials:)

What I am probably looking for is the mirror ball method?

I did observe that he refers to Bryce 6.1 and nowhere that I read did he mention using the HDR render function - is this function new to Bryce 7 and I am possibly looking at an old tutorial?

In any case, I will follow the tut and see where that gets me.  In fact, there are so many more Bryce tutorials than what are available for Carrara, especially for landscapes, that I think I must now buckle down and do try doing all my landscapes in Bryce:)

Bryce 7 is improved for IBL in many ways, but it will do you no harm to learn from the tutorials first.

As for tutorials for Bryce 7 Pro, here’s a couple of beginners tutorials I’ve done recently that people seem to have liked.

Bryce 20 minute beginners project - simple landscape - a tutorial by David Brinnen
Bryce 25 minutes on landscape lighting basics - working with legacy skies - by David Brinnen

There are plenty more where those came from on my channel, and also here http://www.bryce-tutorials.info/

When you get to the point where you have got to grips with HDRI and if you want to make life easier for yourself, here are a couple of products made by Horo and myself which might help.

You would probably only need one of these - depending on the HDRI type favoured by Carrara

Scene Converter
Spherical Mapper

Experience or Horo could tell you which would save you the most time and effort.

 

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Posted: 14 February 2013 11:18 AM   [ Ignore ]   [ # 5 ]
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@Roygee - rendering as 360° panorama won’t help you because you get a cylindrical panorama, not a spherical one as needed in Carrara. This cannot be done in Bryce directly except with the Bryce 7 Pro Spherical Mapper (http://www.daz3d.com/bryce-7-pro-spherical-mapper).

You can render the 6 cube faces (best result) or the two hemispheres. The mirror ball is the most complicated. You will need a program to assemble the individual renders and create a spherical (or equirectangular) projection.

As TheSavage64 proposed, do not save each render but EXPORT the rendered images as *.hdr. Now assembling the renders to a spherical HDRI, you need an HDRI capable graphics program to do so. I would assemble the renders (cube faces) to a vertical cross in Photoshop CS2 or newer, then save the cross as HDR file. With HDRShop, you can open this vertical cross and transform it to spherical. Of course, the spherical mapper renders the scene directly in the spherical projection and if exported as *.hdr out of Brycce, you’re set.

Yes, the tutorials were made for Bryce 6.1, there was no hdr export then. It came with Bryce 7.1 Pro. Also saving a sky as HDRI came only with Bryce 7.1 and you need the Pro version, in the Standard and PLE versions, this option (among others) is disabled.

If you export a rendered image as hdr, it is a true 96 bit per pixel file. But you do not have the high dynamic range you would expect in an image with the sun and deep shadows. What you get is a very finely shaded image with more than the 8 bits per colour per pixel as we get with a LDRI (bmp). Nevertheless, it is of higer quality and will emit nice ambient light.

You can use Bryce to render a scene that can be made ro a true HDRI with very bright light sources and all you expect from an HDRI for IBL. However, this is a tedious and tricky thing to do. I have a 3-part video ready that shows exactly how this is done, but the video is not yet published. The video was done exactly for those who want to create a real high dynamic range panorama in Bryce for using it for IBL in Carrara or Studio (and Bryce).

If your image is to be rendered as backdrop, you have to render it quite large. I have a calculator on my website (see sig) which helps you determining the document size needed. Go to Science > Panorama. If you use it as backdrop in Carrara, be aware that Carrara tone-maps it linearly, it cannot tone-map it with a more sophisticated tone-mapping operator as is built in in Bryce.

As for using it in Bryce - memory is the issue because Bryce is still a 32-bit application and cannot directly address more than 2 GB. And Bryce does everything in memory and cannot bleed over to a HD. If you install LAA, you can go up to about 3.5 GB and can load a light probe up to 6400 pixels diameter, else, much smaller. Bryce, by the way, prefers the panoramic HDRI on the angular projection. David and myself have developed a lens for Bryce, the Bryce 7 Pro Scene Converter (http://www.daz3d.com/bryce-7-pro-scene-converter) which accomplishes this in one go. But this projection cannot be used in Carrara.

I think that’s enough for a start. If you have more question, do not hesitate to bring them forward.

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Posted: 14 February 2013 02:06 PM   [ Ignore ]   [ # 6 ]
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Thanks so much, TheSavage, David and Horo - a lot more information than i expected:)

Bedtime now and so much to digest - I’ll get on it tomorrow and see where this takes me!

Cheers:)

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Posted: 16 February 2013 12:36 AM   [ Ignore ]   [ # 7 ]
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Just to confirm that saving as HDR after the render worked just great - the quality was really good and I could render a scene in Carrara without any lights at all - in fact, I had to turn down the brightness of the HDR:)

David, your beginner videos are great - I’m now going to concentrate on making landscapes in Bryce - hopefully get a decent render to show off here:)

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