Issue with HDRI lighting

[neroe23[TheOne]]

Hello everyone, I've been following LuxRender since last year and I decided to create my own images.
As I had little knowledge with 3DSMax I made some little scenes. But I then discovered the fluid simulation of Blender and I only work with it now. As a total newb, I crawled through the wiki and tried to remember as much informations as I could.
And I finally landed on the "Sun, Sky and HDRI" tutorial, I did everything that was written (I have to say I was quite proud) but I quickly noticed a...problem. Here it is:
What the hell happened to the background quality ??

PS: I'm running on a Windows 7 x64; Intel i7 2600K, GTX460; LuxRender 0.8

[Abel]

What happened to the background quality ?

PS: I'm running on a Windows 7 x64; Intel i7 2600K, GTX460; LuxRender 0.8

It looks like the background resolution is quite low; as the image is wrapped around the whole scene (like a sphere), only part of it will show. This means you'll need quite a high resolution image.

[SATtva]

10000x5000 or higher are quite common.

[neroe23[TheOne]]

Thing is I used the arch.exr file which is used in the LuxMark luxball scene... I took a look at the file itself and the size is about 1024*512. But now the question is why is the luxball scene's background clean ? Is the whole scene downsized or something ?

[J the Ninja]

Thing is I used the arch.exr file which is used in the LuxMark luxball scene... I took a look at the file itself and the size is about 1024*512. But now the question is why is the luxball scene's background clean ? Is the whole scene downsized or something ?

IIRC, the luxball scene has a pretty heavy depth of field added on, that might be fuzzing things up a lot.

[neroe23[TheOne]]

Erm but referring to the tutorial, the last photo which is the final render has top definition reflections. Am I stupid or maybe there is a narrowed version of the same picture. Thanks guys you are full of ideas and the most active devs I know !
Here is the reference:

[J the Ninja]

Erm but referring to the tutorial, the last photo which is the final render has top definition reflections. Am I stupid or maybe there is a narrowed version of the same picture. Thanks guys you are full of ideas and the most active devs I know !
Here is the reference:

That's a reflection, not a visible background. A lot more of the image is visible in a reflection, and it is packed into a much smaller space.

[neroe23[TheOne]]

Oh right, I understand now. Thanks for your help !
PS: I got a few other problems like "velvet aliased shadows", I guess I'll post them later this week because for now EXAMS.

[Meelis]

Yeah even the 10000x5000 pix is way too low resolution for background especially for tele lense and high resolution render.

I remember a while back i measured hdr pixels on render and then on actual hdr map. HDR map was 8000x4000 pix and i had 3x under resolution.
Now when you take account 3 super samples that i used that time, than there was allready 9x under resolution.
Better forgett ideal beautifull magnification in spherical glass surfaces that enlarge HDR map image 5-10 x (W 90x H 90x lower resolution than i need [720 000 x 360 000 pixels HDR map ~ 3,2 TB memory use just for HDR map])

I recommend to use some sort of test grid image as hdr map, so you see where and how much you need pixels.

I was wondering, lets say i make the HDR map myself and i allready know the area where i need much higer resolution on HDR map.
Then i make 2n't image or much higher resolution panorama crop image (don't know how).
Then i also need to match the coorinates - perfectly align the HDR panorama and the high resolution crop (don't know how).
Is such setup possible with 2 HDR maps?

[SATtva]

Rendering with alpha channel and later composing with high-res image would be a LOT easier.