Showing posts with label lighting tutorials. Show all posts
Showing posts with label lighting tutorials. Show all posts

Thursday, October 1, 2009

EXTERIOR SET LIGHTING WITH 3DS MAX

After a long time (near about 7Years) I tried to lit a scene in 3ds Max. I took neutral (only blin with no speculars) shading exterior set and started afternoon lighting with default scanline render. The set looks like this without any lights.
Start with one freeDirectional light to simulate Sun. with settings shdows on with shodow map shadow options. ">


change the bias to 0.05(by default 3dsmax renderer calculates shadow bias as 1.0 but this value takes shadow out from the origin. like this image.
this image shows corrected bias value for this set. so the shadows will stay at the origin of the geometry. This occurs because of the shadow map calculation by scanline render. It creates a 2d map of the geometry from light's view. bias value controls the placement of the shadow map.












Now we need to add a fill light to eliminate the darkness created by keyshadows. for this I used a freeSpot light with values like this and position that light somewhere around opposite to the sun light direction.

and render output with fill light and sun light looks like this


Now back side of the set is too dark and fill light is not reaching there. So create a point light and include only that surface to the light illumination and shadow parameters and the light settings should be like this; use inverse square as the decay rate. it restrics light to a limited distance. by default all the cg lights comes with infinite range. we can control with decay and attenuation parameters. Rendered image with fill light added for the back side of the set should look like this




Now we will start adding more lights for detailing and simulating the bounce of the sun.add bounce for the balcony. usually in midday noon time bounce is more and it bounce the texture/shader color of the nearby geometry since we have only gray color shading so the light bounces with default sun light color. these are the settings for balcony bounce light. I used a omni light as the bounce light and included only balcony base geometry to lights illumination and shadow parameters ( include and exclude parameters are similar to Maya make/brake light links attribute). light settings are like this;


and the rendered image should look like this

Now balcony top fill...

Now adding bounce light for fabrik in the foreground with a free spot positioned from the bottom with this settings....

and render out put is like this....

Now add details to pillars by using free spot.(spot lights are more orthodox lights with less render time, I encourage the usage of spot lights more often)when ever you get confused with which light illuminating which geometry you can simply unchek the lights in lightlister(cool tool in 3dsMax) and chek the individual lights illuminating geometry! render output with added details to the pillar.

Now start adding details to the wooden rack in the foreground. with usual spot lights. this is the render output...

Now small pillar in the background.

Fabrik key in order to match sun illumination.....



Bounce light for Small balcony right side of the set.....

after adding global fill for floor and fill for backside geometry.. the image should look like this.

Friday, June 26, 2009

MAYA 2009 NEW LIGHTING FEATURES

Hey guys let we explore new lighting features in MAYA 2009. Here is a simple tutorial using MAYA-DIGITAL FUSION. This tutorial based on the newly introduced render passes in lighting. The task is to match the look and feel of this image.

modeled by Juan Carlos Silva.

Maya 2009 allows us to render our scene in to multiple passes like Ambient Occlusion,
diffuse material color, specular, shadow, indirect, incandescent, translucence, indirect etc.. this method gives us greater comfort to fine tune the output quality in post by using softwares like Fusion,shake, AF etc.... let we start lighting.

Maya scene looks somewhere like this


Now create render layers for floor,occlusion,key,fill,rim,shadow and topfill.
after creating all the render layers your layer editor should look like this


Use four lights key,rim, fill and topfill. add each light into its respective render layer.

Now the important task adding passes to layers. Make sure that mental ray selected in render using option in your render settings tab. it should look like this...

in extra to light passes our character needs one occlusion pass. light is not required for occlusion pass. to get the correct occlusion you have to make some changes in the render settings window. first go to the passes tab and click on create new render pass button, this will open a another window contains different render pass options. choose AO, diffuse material color passes form the window. like this.

after creating render passes in order to render with the particular render layer we need to associate that pass with render layer by adding the render passes in to associate passes window. Now its time to set the values for Ambient Occlusion calculation. Ambient Occlusion option is available in indirect tab. opt for final gathering and Ambient Occlusion set the final gather accuracy 100 and rays 512 in Ambient Occlusion. like this

for all the light passes choose maya software as renderer.Be sure every renderusing option must be overrided.(except for key we need specular pass for the key light) for key light add only specular pass. render key shadow on the floor as a seperate pass. for this select character and floor create a render pass rename that render layer as "Shadow". assign use background shader to floor. select the robo and go to the attribute spreadsheet window switch off primary visibility and recieve shadow options in the render tab.finally add key light in this render layer. select all the floor items and switch off cast shadow option. this will give you rendered shadow in alpha channel. adjust the light positions as required by the scene. turn on the shadows for each and every light. now its time to render. set appropriate project directory and render single frame using maya batchrender. It gives images like this.

and all the passes looks like this image.


now its time for compositing... open digital fusion and import all the images into.
start with char_diffuse material clor connect to occlusion node and choose multiply in apply mode option. like this

keep on constructing the Fusion flow... and final flow should look like this.


and your final image in fusion will look like this.



so this is the basic workflow for Maya 2009 render passes. practice it and enjoy. if you have any doubt just mail me on "cglighting@gmail.com"... more tuts are on the way coming soon keep visiting my blog.