baba147 Posted October 22, 2007 Share Posted October 22, 2007 Hi everyone, I am trying to Render different passes to do composition in photoshop... Also rendering a few render elements...all goes fine but vraydiffusefilter is rendered very low res... i created very simple scene to check, and diffusefilter renders perfect...what i found was that if you have vraysun in ur scene then vraydiffusefilter is rendred low quality(visible non-antialiased sharp edges and blury textures)... vraysun is not the only thing...i tried deleting vraysun but still got low quality in vraydiffusefilter... may be its UVW modifiers... may be it has something to do with default lighting... couldnt find anything in vray help... Anyone knows why its happening??? i will check UVW and default lighting meanwhile... Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 All works fine. I have not troubles with my diffusefilter renferpass. Show us some images plz. left - render, right diffuse filter channel Link to comment Share on other sites More sharing options...
baba147 Posted October 22, 2007 Author Share Posted October 22, 2007 well...it works fine if my scene doesnt contain any light + the default lights checkbox is checked in vray global switches...here are my results of test scene...it renders worse if light is vraylight or vraysun. Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 i use sun+sky. GI. no troubles. never heard about it. send me your scene. i`ll try to check it. version of max and vray? Link to comment Share on other sites More sharing options...
baba147 Posted October 22, 2007 Author Share Posted October 22, 2007 i am using vray 1.5 RC5...with 3ds max9 sp2 32bit.. i am attaching the simple test scene...just try it with default lights ON in vray global switches rollout...then try it with default lights OFF... Compare the two results and show me... and thanks for the help... Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 hm, there is ni problem, belive me. i`ll try to explain you what happened. 1. deff light on by default there 2 omni hidden light in the max when you render - aa can finde contrast pixels and work fine 2. deff light off No light in the scene. aa can`t finde contrast filter and doesn`t work you haven`t aa in render. render is not good 3. add custom light default light doesn`t work (checked or unchecked - doesn`t matter) when there are another light in the scene. so AA work fine! just add sun or vraylight (or other light) in you scene and render it. 1 and 2 result will be same as your pictures 3 will be as mine render Link to comment Share on other sites More sharing options...
baba147 Posted October 22, 2007 Author Share Posted October 22, 2007 Thanks dagor for the help...but as i was checking ur third option, i found something... Low quality edges appear where the object is totally dark and in shadows... When using GI, the light reaches almost every surface so there are no pure shadows...and it works fine with GI... i am attaching, my experiment...in one scene i used many lights to keep all sides of the cube lit...it produces good results... in other scene, i removed the extra lights and side of the object is in complete darkness...it produces low quality results...the same happens if the overall light intensity is too low... and it works with default lighting because default lighting lights objects without creating shadows...turning default lights off makes whole scene dark... try doing this: re-render ur first render in this thread...this time move the light somewhere else so the dark side of the object faces camera... and make sure GI is OFF...and the dark side is in shadows...also put some texture on that grey block in first render... by the way, i shouldnt be correct because, in principle diffuse filter has nothing to do with lighting... but i keep getting the bad results... Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 i use render elements not so much, but... ok, it seems you are right. but i think it`s logically. tell me did you realy need this part of diffuse filter in good quality? in render this area completly dark. so after compositing - you will have dark images! if vray will be filtering this area - it will be very long render! it`s unnecessary. let me know what you think about it. Link to comment Share on other sites More sharing options...
baba147 Posted October 22, 2007 Author Share Posted October 22, 2007 actually, i am trying to fake GI...there are total four passes(ofcourse, they are rendered with GI OFF): 1. Ambient Occlusion..(for soft shadows...using a vray script for AO) 2. Direct sunlight...(for hard shadows and direct lighting) 3. DiffuseFilter...(for flat shading to prevent shadows becoming too dark due to first two passes) 4. Flat color pass...(just flat colored objects with no texture, to aid in making selections in photoshop...this pass remains hidden) after rendering these passes...i take them to photoshop...when soft shadows and hard shadows are blended from first two passes, them resulting image is too dark and doesnt simulate the GI well... then i blend the dark image with diffuse filter...transparency of diffuseFilter lets me control the amount of light in whole image... Then i add alpha maps to layers to control light in specific areas of image...this is where 4th pass is used... by the way, i looked for a script which renderes 100% self-illuminated objects...since changing all the materials is not a good idea...i couldnt find any script... i am attaching the composited images...u can see a few non-antialiased edges due to diffusefilter... also you can see that the amount of lighting can be changed within photoshop, the main advantage of compositing. its not a quality render though...I am not much of good designer... since i am trying to fake GI...so comments and critics are welcome on GI/lighting/shadows etc. Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 first of all - it`s realy simple exterior for fakeing gi. gi work very fast in this scene. but for glass wall exterior you can`t fake GI like you want! you`r glass will be transparent but diff filter will have glass color! so you will need additional render for diffuse filter beyond glass. it`s to long! if you want to tweak amount of lighting - render it in 32bit image and tweak exposure or gamma in photoshop. for whot you show - you need only beauty render and Flat color pass (it can be MTLid, OBJid, Rende ID passes) for selection. you can select by mask your building and tweak curve - it`s fake of amount of light . there are alot of channel wich you can use for tweak amount of light in scenes. for example Raw Lighting. here is short example of channel. http://www.spot3d.com/vray/help/150R1/examples_renderelements.htm sorry, but i realy dont know what you are looking for, because there are more chanel that you need in vray wich you can use for compose and tweak image. you only need to note some thing! 1. use Digital Fusion instead Photoshop for compositing, because it node based software and in have ADD compositing mode (photoshop haven`t ADD blending change, you can merge in ADD mode layers, but not tweak it after merging) 2. don`t use color mapping in render (even though Don`t affect color checked) because color mapping apply not only to final image but also in render stage so you can`t compose image from passes exacly as your RGB render. Use only linear color mapping. 3. Vray it`s very fast render, so use it`s features in 100%, don`t think out your own features )) so hope it`s help you! Link to comment Share on other sites More sharing options...
baba147 Posted October 22, 2007 Author Share Posted October 22, 2007 you are right... and Thanks for the added knowledge... As you said about other passes, i was already thinking to use shadow pass and light related passes...the main reason for faking GI was due to its long time... i had rendered very similar picture with GI...and got similar(somewhat better) results and it took 6 hours... perhaps, i needed to change GI settings to speed up rendering process... what do you say about 6 hours time??? i guess, this is my last question to you... And thanks alot for helping alot... also i would like to see your work, if you have it posted anywhere... Link to comment Share on other sites More sharing options...
dagor Posted October 22, 2007 Share Posted October 22, 2007 i think 6 hours it`s long! but it depend on your PC, image size, rendersettings. for example you show try next: phiscamera+sky+sun for lighting, Irradience map + Lightcash. just take one of your work, go in WIP section and try different method of GI. Read help, there are alot of useful informations about settings! So about my work - i`ll show some of pictures. Link to comment Share on other sites More sharing options...
baba147 Posted October 23, 2007 Author Share Posted October 23, 2007 i was reading that render element examples page...its written there that vray doesnt anti-alias areas of image which are in complete darkness...it does this to speed up rendering process...so it explains the reason behind actual topic of this thread... my pc is: cpu p4 2.8 Ghz ram 1.5GB OS win vista Graphics card : 256MB Ati radeon and render settings: image size : 1024x768 Irradiance map quality : preset high no secondry bounces engine... Link to comment Share on other sites More sharing options...
dagor Posted October 23, 2007 Share Posted October 23, 2007 it`s realy long rendering. try to use for irmap -1 -3 (you can modify hi preset) for second use lightcash in screen mode with 1000-1500 subdivse set prefilter 100 or near it, no filter. for AA use QMC without filtering sun+sky+phiscamera. will work fine Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now