BnE
10-22-2003, 08:45 AM
hi here, i just found some interesting things about faking soft reflection, i'll try to explain them and i hope it will be usefull to people... if someone knows a better way to achieve the same result please tell me. i did this in lightwave but it should work in any other package. :)
so here was my problem : i want soft reflection but it takes extremely long to render... see picture 1 : render time is 1min44sec. i have 65% reflection blurring, 30% reflection and AA medium(9 passes), adaptive sampling enabled. thought the blurred reflection is very accurate, it's waaaayy to long for a picture like this.
here is the trick i found to fake soft reflection. first turn off blurred reflection and apply to your soft reflection surface a very small fractal noise bump(i used 0.01um). layer is 100% opacity, 100% texture value and the whole bump is 100%. if you render now, you'll see the beginning of the blurred reflection( picture 2). but i want to make it softer, because there is to much noise. so i'll render into two different passes. one is the beauty pass, so turn off raytracing reflection and make your soft reflection bump layer 0%. render , picture 3 is what you should have. now add render buffer view to your processing tab in order to have the reflection pass. enable raytrace reflection, make your soft reflection bump layer 100% and render. picture 4 is what you should end up with. now, load beauty pass and reflection pass into photoshop. put the reflection layer on top of the beauty one. change the reflection blending mode from normal to screen(i think it's the name of this blending mode in english..). add a very small blur to the reflection layer. it should look like picture 5.
here are the render times for the bump trick. AA is medium and adaptive sampling is on. reflection pass : 35sec, beauty pass : 0.8sec, photoshop compositing : 2sec :D .
thought the bump trick is not as accurate as the real soft reflection, render times are much faster. there's a big difference between 1.44 min and 38sec for a picture that is almost the same...
i hope this will help peole to achieve very realistic refregirators!:beer:
sorry about the way i had to attach all the picture, i did this mini tut at work and i dont have any ftp client there... :hmm:
so here was my problem : i want soft reflection but it takes extremely long to render... see picture 1 : render time is 1min44sec. i have 65% reflection blurring, 30% reflection and AA medium(9 passes), adaptive sampling enabled. thought the blurred reflection is very accurate, it's waaaayy to long for a picture like this.
here is the trick i found to fake soft reflection. first turn off blurred reflection and apply to your soft reflection surface a very small fractal noise bump(i used 0.01um). layer is 100% opacity, 100% texture value and the whole bump is 100%. if you render now, you'll see the beginning of the blurred reflection( picture 2). but i want to make it softer, because there is to much noise. so i'll render into two different passes. one is the beauty pass, so turn off raytracing reflection and make your soft reflection bump layer 0%. render , picture 3 is what you should have. now add render buffer view to your processing tab in order to have the reflection pass. enable raytrace reflection, make your soft reflection bump layer 100% and render. picture 4 is what you should end up with. now, load beauty pass and reflection pass into photoshop. put the reflection layer on top of the beauty one. change the reflection blending mode from normal to screen(i think it's the name of this blending mode in english..). add a very small blur to the reflection layer. it should look like picture 5.
here are the render times for the bump trick. AA is medium and adaptive sampling is on. reflection pass : 35sec, beauty pass : 0.8sec, photoshop compositing : 2sec :D .
thought the bump trick is not as accurate as the real soft reflection, render times are much faster. there's a big difference between 1.44 min and 38sec for a picture that is almost the same...
i hope this will help peole to achieve very realistic refregirators!:beer:
sorry about the way i had to attach all the picture, i did this mini tut at work and i dont have any ftp client there... :hmm: