HDRI - vray - max ?

[bernhard]

Hello friends !

I created my own hdr images years ago with my camera and a mirrored sphere.
Today, I would like to know, if I can render with max & vray an hdri from a specific scene ?

Does someone know if that is possible ?
And if so, how you can do that ?

Thank you for every little help,
bernhard

[instinct]

as a spherical env map or an HDRi version of the final image ? Both is of course possible. Just save to a float format basically...

Regards,
Thorsten

[Clifton Santiago]

Every image I render is HDRI, though I use .EXR format.

[bernhard]

hmmm

Well, baiscly you mean a 32bit format, right ?

When I made my real life hdr images, I made about 6 photos, with a different shutter speed. After that I used HDR Shop to generate the .hdri

now in max, I render with vray a picture as 32 bit ?
and that's pretty much it ?

for a spherical shot it would be nice to have something similar like a fishey camera.
Or do you guys mean a totally different way to do that ?

thank you for every little help,
bernhard

[Clifton Santiago]

Oh, you're asking about panoramas, not HDRI specifically...

Just put in a max camera, specify spherical camera in the vray camera settings, and override FOV at 360. This gives you an equirectangular panorama that can be converted to QTVR or Flash panorama using something like Pano2QTVR.

[bernhard]

hmm

Yes, I think a panorama cam in combination rendering a hdr would be fine for my tests.

I never rendered a hdr directly from vray - so I don't know if it supports the floating point values, I would need for. I will test it.

@Cam:
I was looking for the spherical settings in the vray cam settings, but couldn't find.
Hmm, can you let me know where exatly I can find it ?

thx for every little help,
bernhard

[Clifton Santiago]

Okay, I think you are confused about some pretty basic things. First I recommend you read up on what HDRI means. Maybe start here: http://en.wikipedia.org/wiki/HDRI

Whenever you render to a frame buffer (or not, as in the case of .vrimg), as long as there is no clamping, you have (potentially) a full-float HDRI. This essentially means you have full exposure range built into each image. As you can see in the VFB, when you enable exposure control, and slide the exposure slider, the image goes from completely over-exposed (appearing white) to completely under-exposed (appearing black). When you save the image as .HDR or .EXR 32-bit, you have saved an HDRI. As long as the post-production app you use after supports 32-bit format, you will maintain the full-float values.

Panoramas are an entirely different thing. If you render a panorama in a frame buffer, and save as .HDR or .EXR 32-bit, you have an HDRI panorama. If you save it as a JPG, you have an LDR panorama.

I thought I explained clearly before, but here is a step-by-step to render a 360 degree panorama in Vray:

1) Create your scene. Set up a Max camera (not vray physical camera). Set your render size to a 2:1 proportion.
2) Open the Vray:Camera tab
3) Change camera type to Spherical
4) Click Override FOV
5) Change the FOV to 360
6) Click Render

The resulting image is a 360 degree equirectangular panorama.

[bernhard]

thx

@hdri:
well, for that point I am very clear and not confused, I want to create a panoramic hdri like a wrote. I made my own hdris years ago in reall ife, but never made one directly from the render, and I didn't know that you can save directly from the render a hdri. . Thx for the update.

@camera:
you meant the vray camera settings in the render options.
now it's clear for me concerning the camera, because I thought you meant a vray cam and the settings in the poperty stack.

But is the panorama only possible with a max standard cam ?
What if you use a vray physical cam, with a specific shutter speed and ISO ?
Or does it not work with a vray cam ?

I made a quick test, and when I switched to my vray physical cam, it didnt' work.
But maybe you know a away...

thx,
bernhard

[Clifton Santiago]

The VrayPhysicalCamera works like a physical camera. As such, you would need to do a panorama like you would in reality, i.e. use a wide FOV, render multiple views, and stitch them together.

[bob-cat]

Or you could do what you did years ago, but inside max.
Pop a sphere into the scene, put a chrome/mirror material on it and render to a hdri image. Then a couple of trasformations in HDRI shop and you have your hdri!

[^Lele^]

In any case, being able to output to an hdr format will allow you to expose the image later.
The goal is to create an environment, not to expose it.
It will get proper exposure once that HDR it's in the scene as BG, and you'll render through a physcam.

[bernhard]

ok

Ok, thank you all for your comments, I really appreciate that much.

@bob-cat:
yes, that's what I thought first, I make it like in real life - but I thought maybe it can be done easier and faster in max.

thx for all you thoughts, that helped me a lot!

bernhard