Tweet
Hi all,
this is quite long but pls bear with me.
I think this is my first post (not its actually my 8th, but I didnt remember ever posting something, lol), eventhough I've been reading through the forum for a while now. Thank you all for the great help, tips & tricks etc. you've provided. Though I only read in the forum they helped immensly and I think it's time to give something back, but I'm not sure if this is known already. I also have some problems which are described further down.
so here it goes (for everything I used Irradiance for 1st and Lightcache for 2nd, settings were medium with high h-subdivs and interpolation | a sampling rate of a 1000 with no filtering, respectively. I think the settings are appropriate, correct me if I'm wrong
):
I've been reading up on the linear workflow thingie and through that ended up in the "basic comping of a vray scene" or something like that. The problem I kept having (no matter which space I worked in, Linear, Exponential or whatever else there is), is that my comped image never looked exactly like the normal render (mind you, I did all the comping in photoshop). The comped image was close but just never there, so I've been trying out a few things with the matte property since then.
My Goal was to get Vray to burn Gl-Maps for me (essentially lightingmaps + indirect illumination), which were to be used in a realtime engine to make an architectural walkthrough; which is far easier said than done. Btw, I'm using the latest Vray build and Max 7. Anyhow, at first I tried to do it with comping, but while the lighting- and GI-maps renderd by Vray + photoshop left something to be desired, like lightingmaps being jagged, gi maps with splotches or other artifacts etc., etc.. maybe I was doing something wrong, but dont think so...
So here's what i found:
I made a test of an interior scene, lit only by interior lights, like spotlights and omins plus a couple of vray lights where needed, the scene was then fully textured and after making a few low-res test renders and saving them (for reference) I went ahead. I put a Vray material wrapper on ALL materials (some had one already, others were vray mats) and checked "matte surface" and "shadows" below it in the vray mat wrapper on all materials. In the Render Settings in the Vray frame buffer rollout I ckecked "Save separate G-Buffer Channels" and saved the file as jpg, with no compression. In the Color-Mapping rollout I didnt choose any of channels, since I only wanted the RGB channel, which is saved automatically.
After I hit render I expected to see some weird result but it worked! The lightcache is computed normally (check "show precalc") as if no matte surfaces were used. But the irradiance map clearly shows it afterwards, a perfect GI-Map, no jaggies, no noise nada! Yeah! wow was I proud of myself. (Since I worked in linear space with correct gamma values etc. and the color correction thingie in the vray VFB it was quite a mission to get the textures baked, because for every texture rendered I had to quickly click on the color correct button, adjust the curve, reset the other sides tangents, close it and hit the apply button. This can be quite fun to do when your map is like 128x128 and gets rendered in like 2 secs. speed kills )
(another tip to save time: I let Max do the infamous "automatic unwrap" which in my opinion sucks carrots, but instead of having to unwrap all the complex geometry yourself, let Max do it initially, afterwars just go and edit the UV's in the automatic unwrap rollout, works like a charm, because mostly all you have to do is scale things and delete the UV's you dont need. This is much better than deleting actual faces (geometry) because this can lead to light and shadow leaks, in my experience that is)
so as for as comping goes this really means that you can take the rendered image and combine it with the diffuse image to get exactly the same result. To be honest, since this works flawlessly in the realtime engine and I dont need to combine raw light and raw gi anymore I havent tested the result in photoshop yet, but I'm 100% sure it works.
okay, so much for my tips, the following are problems I experience with the above mentioned method of using matte surfaces to get GI-Maps.
1. As soon as I place a daylight outside (obviously)of the interior, which most of the time was a IES sun or a direct light with vray shadows, the render of the GI-Map goes haywire. ok thats pushing it, but interior and exterior surfaces are either much too dark, much to bright or have way too much color bleed. when I switch of the exterior light, everythings peachy...? dont get it, may be a bug. Ive tested almost everything I can thing of but always with the same result. Any ideas?
2. somehow it seems that my baked maps show these rainbow like artifacts around shadowy areas. I'm sure you've seen it before it also happens when you heavily compress a jpeg. I've tried TGA etc. but always same result, and that looks really strange in the realtime engine Any ideas?
3. Since Vray doesnt set the map names saved from the G-Buffers automatically per Objectname (like the Max RTT) you cant let a scene render overnight because all the maps will just be overwritten since the filename entered obviously doesnt change. Is there a way to fix this?
4. The thing with the color correction tool in the vray VFB. Is there a way to make it keep its settings? I have never tried maxscript and have no idea how it works... and I know it keeps the settings when you render normally, I mean i RTT mode
this is it, excuse the long post but I thought "if I do it, ill do it properly!"
cheers,
yves
this is quite long but pls bear with me.
I think this is my first post (not its actually my 8th, but I didnt remember ever posting something, lol), eventhough I've been reading through the forum for a while now. Thank you all for the great help, tips & tricks etc. you've provided. Though I only read in the forum they helped immensly and I think it's time to give something back, but I'm not sure if this is known already. I also have some problems which are described further down.
so here it goes (for everything I used Irradiance for 1st and Lightcache for 2nd, settings were medium with high h-subdivs and interpolation | a sampling rate of a 1000 with no filtering, respectively. I think the settings are appropriate, correct me if I'm wrong
):I've been reading up on the linear workflow thingie and through that ended up in the "basic comping of a vray scene" or something like that. The problem I kept having (no matter which space I worked in, Linear, Exponential or whatever else there is), is that my comped image never looked exactly like the normal render (mind you, I did all the comping in photoshop). The comped image was close but just never there, so I've been trying out a few things with the matte property since then.
My Goal was to get Vray to burn Gl-Maps for me (essentially lightingmaps + indirect illumination), which were to be used in a realtime engine to make an architectural walkthrough; which is far easier said than done. Btw, I'm using the latest Vray build and Max 7. Anyhow, at first I tried to do it with comping, but while the lighting- and GI-maps renderd by Vray + photoshop left something to be desired, like lightingmaps being jagged, gi maps with splotches or other artifacts etc., etc.. maybe I was doing something wrong, but dont think so...
So here's what i found:
I made a test of an interior scene, lit only by interior lights, like spotlights and omins plus a couple of vray lights where needed, the scene was then fully textured and after making a few low-res test renders and saving them (for reference) I went ahead. I put a Vray material wrapper on ALL materials (some had one already, others were vray mats) and checked "matte surface" and "shadows" below it in the vray mat wrapper on all materials. In the Render Settings in the Vray frame buffer rollout I ckecked "Save separate G-Buffer Channels" and saved the file as jpg, with no compression. In the Color-Mapping rollout I didnt choose any of channels, since I only wanted the RGB channel, which is saved automatically.
After I hit render I expected to see some weird result but it worked! The lightcache is computed normally (check "show precalc") as if no matte surfaces were used. But the irradiance map clearly shows it afterwards, a perfect GI-Map, no jaggies, no noise nada! Yeah! wow was I proud of myself. (Since I worked in linear space with correct gamma values etc. and the color correction thingie in the vray VFB it was quite a mission to get the textures baked, because for every texture rendered I had to quickly click on the color correct button, adjust the curve, reset the other sides tangents, close it and hit the apply button. This can be quite fun to do when your map is like 128x128 and gets rendered in like 2 secs. speed kills
)(another tip to save time: I let Max do the infamous "automatic unwrap" which in my opinion sucks carrots, but instead of having to unwrap all the complex geometry yourself, let Max do it initially, afterwars just go and edit the UV's in the automatic unwrap rollout, works like a charm, because mostly all you have to do is scale things and delete the UV's you dont need. This is much better than deleting actual faces (geometry) because this can lead to light and shadow leaks, in my experience that is)
so as for as comping goes this really means that you can take the rendered image and combine it with the diffuse image to get exactly the same result. To be honest, since this works flawlessly in the realtime engine and I dont need to combine raw light and raw gi anymore I havent tested the result in photoshop yet, but I'm 100% sure it works.
okay, so much for my tips, the following are problems I experience with the above mentioned method of using matte surfaces to get GI-Maps.
1. As soon as I place a daylight outside (obviously)of the interior, which most of the time was a IES sun or a direct light with vray shadows, the render of the GI-Map goes haywire. ok thats pushing it, but interior and exterior surfaces are either much too dark, much to bright or have way too much color bleed. when I switch of the exterior light, everythings peachy...? dont get it, may be a bug. Ive tested almost everything I can thing of but always with the same result. Any ideas?
2. somehow it seems that my baked maps show these rainbow like artifacts around shadowy areas. I'm sure you've seen it before it also happens when you heavily compress a jpeg. I've tried TGA etc. but always same result, and that looks really strange in the realtime engine
Any ideas?3. Since Vray doesnt set the map names saved from the G-Buffers automatically per Objectname (like the Max RTT) you cant let a scene render overnight because all the maps will just be overwritten since the filename entered obviously doesnt change. Is there a way to fix this?
4. The thing with the color correction tool in the vray VFB. Is there a way to make it keep its settings? I have never tried maxscript and have no idea how it works... and I know it keeps the settings when you render normally, I mean i RTT mode
this is it, excuse the long post but I thought "if I do it, ill do it properly!"
cheers,
yves
...someone? sorry, I'm anxious to hear your opinions... so come on, go ahead, dont be shy! 
):
. But I would still be faced with noise, interior lights being render incorrectly and the result being darker than it should be. all things which could be avoided with matte surfaces, in my opinion at least.
no wonder after my first post 
)
Comment