Background Problems...

[juan.carlos.rioja]

Hello folks

I have problems when I try to use a background for my scenes. When I use a .jpg of a sky for example, the background turns black. The solution I found for this problem is to turn off the exposure of my physical camera, but when I do this all my scene turns extremelly bright. Once again, the solution I found for this is to set a .HDR for my GI but it spends more time rendering.

Somebody knows a better solution for using a .jpg background in my scenes???... thanks

[dcauldwell_cg]

Re: Background Problems...

Your jpg sky is probably turning black because its multiplier needs setting a lot higher (see 3 below)

Background Options

1 No background – insert one afterwards in PS – sometimes the safest and easiest and you have the most control over the output. Background can also be site specific (buildings, trees etc). In effect this is the 'photomatch' technique. For an example look at Toms work here http://asgvis.com/index.php?option=c...17331#msg17331

2 Use a HDR Image e.g. Spectralogue, 1000Skies.com, etc. – This gives you the advantage of providing an image in your reflections, but often res is so low that they make poor (low res) backgrounds. You can use these to illuminate the scene if they have been prepared properly.

3 Use a jpg - as 2 but these cannot illuminate the scene. Again hi resolution bitmaps are available – up to 14000pix wide. With the physical camera ‘on’, the bitmap multiplier (environment-background-bitmap multiplier) needs to be set at approx 15000 for it to show up

4 Use billboards – you can add your image into a emissive layer in the billboard, thus they have some of the properties of 2. Need to take care in positioning these so they provide the reflections in glass where its required. Adjust the emissive layer intensity to adjust the brightness.

5 Combination of 2-4, then insert a background in PS as 1.

They all work, and have their own advantages and disadvantages – none are perfect. Best would be 2, if you can get a high quality, hi-res HDRI, of your specific site (unlikely!) but the best also tend to be huge 100mb files.

So take your pick.

David

[juan.carlos.rioja]

Re: Background Problems...

thank you david... i'll try them right now