4K SKYDOME?

Malandar

Anyone know if therer are any skydome products that have 4k textures? I have found myself struggling to find  some that don't look like crap in a 4k render. I rendered out a picture and everything about the picture is fine, but for the sky which looks low res so it ruins the render...

Gordig

polyhaven.com has HDRIs up to 24K.

margrave

Don't confuse the size of the HDRI with the size of your render. A 4K HDRI will look terrible since the texture is only 4096x8192.

ragamuffin57

margrave said:

Don't confuse the size of the HDRI with the size of your render. A 4K HDRI will look terrible since the texture is only 4096x8192.

 

Thats good to know  what would being in your opinion is a good resolution for a hdri if wanted to use in a render and not just a light source

Malandar

I am actually not looking for HDRIs I am just looking for textures for a skydome that are in 4k. Thanks for the link to polyhaven though, I never knew about that site.

Horo

Generally, divide 360 degrees by the camera horizontal angle of view in degrees (that's what you will see in your render), then multiply the horizontal pixel size of your final render with that value. Example: camera angle of view 60 degrees, 360/60=6, your render size is 4000 pixels wide so 4000 x 6 = 24,000 that's the minimum horizontal pixel size the HDRI should have to get one HDRI pixel for every rendered pixel (5/6 of the HDRI are not seen in the render). If you use depth of field and the HDRI in the distance gets blurred, a smaller HDRI will also do.

MelissaGT

I'm confused...isn't an HDRI the same thing as a skydome when it comes to Iray?

Horo

An HDRI is a High Dynamic Range Image with not only 256 steps between black and white  (16 Million colors mean 256 red x 256 green x 256 blue, the dynamic range is still only 256:1) while an HDRI can have a dynamic range of several hundred million to 1 (32-bit single precision floating point values for each red, green and blue (96-bit TIF) or half precision floating point (EXR)). An HDRI can be any image.
In a 3D application, we usually define an HDRI as an image in the spherical projection that can be mapped around a sphere (like a world map) and used to light a scene and also be used as backdrop - appropriately tone-mapped so it can be displayed.
A skydome can also be an HDRI but instead of 360 degrees x 180 degrees including zenith and nadir, it is usually 360 x 90 degree and only covers from the horizon up to the zenith, leaving out horizon down to the nadir that is just one color. Actually, such a skydome can also be very useful.

 

glaseye

Horo said:

A skydome can also be an HDRI but instead of 360 degrees x 180 degrees including zenith and nadir, it is usually 360 x 90 degree and only covers from the horizon up to the zenith, leaving out horizon down to the nadir that is just one color. Actually, such a skydome can also be very useful.

For those interested... an example of a mentioned above (non-HDRI) skydome would be my own SkyDome + expansion-sets, availabe at ShareCG. An old one by now, made for use with Poser/Firefly or DS/3Delight, but may still be usueful....