Report Day 14 : 25 July 2013
Summing Noises
Instead of using diffuse color, we now use noise to drive the colors.
The same set up is used by creating a material shader builder and using the surface model node. However we use displacement node. We learn this at school from Mr Ron and it uses the same concept. However, we only use displacement bound. For this tutorial, we learn re-dice displacement and true displacement.
The same set up is used by creating a material shader builder and using the surface model node. However we use displacement node. We learn this at school from Mr Ron and it uses the same concept. However, we only use displacement bound. For this tutorial, we learn re-dice displacement and true displacement.
luminance - it takes in rgb color (vector) and returns a value.
re - dice displacement - it occurs when there is an extreme amount of displacement. Redicing will redice the shaded displacement to give it a more regular shape.
true displacement - true displacement actually moves the position of the points on the geometry and not just giving it a bump.
Lesson 5 - Light Objects
v test assest
v viewport lighting options
v shelf tools
v point light
v deep shadow maps
v ray tracing
v light type
Headlight - do not show lights on scene (default lighting)
Normal lighting - show lights on scene
High Quality Lighting -
I can right click on each of the parameter and control whether i want to see the diffuse, specular, ambient and emission, this allows us to see the difference on the 3d space interactively without render, although rendering is more effective.
Ambient light is strictly not recommended as its a making all the color values lighter, like adjusting brightness of an image in photoshop.
Depth Map Shadows
When using a depth map shadow, an image is created and its stored in a temp folder.
I found a good read about deep shadows and the pros and cons of using it.
Ordinary Shadow
|
Depth Map Shadow (Deep Shadow)
|
2D image rendered from a light
|
2.5D image rendered from a light
|
Each pixels representing the distance to the nearest surface
|
Each pixels stores multiple value of each surface the light hits
|
Use to determine which surface are visible to light and shadow
|
Are able to calculate shadow cast by translucent surfaces
|
Deep shadow stores 2 channel, Pz and Of. Pz store Z depth, depth from the light to the geo. Of, the total opacity of the Z depth. It is good for compositing.
Naming Convention to store the deep shadow rat file
$HIP/dmaps/{$OS}_dshad_$F3.rat
$HIP - Directory
dmaps - Name of folder
{$OS}_dshad_$F3 - Naming Convention of the light (eg. pointlight_dshad_001)
Render
One important thing to take note, when regenerating depth map shadow always remember to click the render button
Depth Map Shadow Parameters
Shadow BiasThe larger the obj the greater the value of the shadow according to how much you want the shadow to be lifted.
Line, Grid and Disk are area lights
Sphere and Geometry are volume lights
Distant and sun are mostly used in an environment scene
Spot Light
The most important parameters of the spot light is cone angle, cone delta and cone rolloff.
Cone Angle
The higher the value, the bigger the cone angle.
Cone Delta
Cone delta and rolloff works together. Cone Rolloff make the hard edge more soft.
Area Light
Area light gives a softer shadow however, a noisier render. To reduce the noise, increase the softer quality.
Volume Light
Volume light give a very nice soft shadow and give a realistic render. However, it takes a longer render time.
By using the attenuation value with the intensity we could get effects like this.
Environment Light
Environment light gives to all areas.
One thing I did know is that I could light up a scene really fast by using an environment light.
Blasting a sphere and taking only 3 primitive. Then using the portal light in the environment light node (Under the render options, tick the portal geo and attach the geo into it)
This will only enable light to emit from the primitive. With this technique, I am able to light a scene really fast.
Lesson 6 - Light Rigs
In the first part of the lesson, I learn a bit more on how to use the sky light.
When we click skylight, two nodes would appear skylight and sunlight
I can put latitude and longitude values and even add location and time to suit the scene. That is something I found really useful.
In the next, I learn how to use the three point lighting node. When you use the node, you will get three different lights, key, fill and rim light. I could interactively move my three point light to another I want also rotate them.
It also useful to add your camera into the three point lighting under "look at camera"
It will orient the light towards the camera so if we make changes to our camera, it will always have consistent lighting.
No comments:
Post a Comment