[vfx] work notes 3

Flicker Expression

If you want to generate a curve with random values between 2 and 8 with a (low) frequency of 1 peak every 5 frames this is the formula:

(random(1,frame*0.2)*6)+2

(random(seed,frame*frequency)*amplitude)+valueOffset

If you want a curve containing random values between 0 and 1.

(random(1,frame*1)*1)+0

simplified version : random(1,frame)

Break it up

• rooftop bricks : break it up, some big, some small, less straight line, slight color variation
• fx expanding spell : don't expand like a circle, break it up, more starfish like, more organic
• fx spell trail dissipation : use wind to break up the straight line trail
• walls : add dirt, add moss, don't be too clean
• heat haze : break it up, some small, some big, some have some holes

Framehold alembic

how to framehold anim/cfx crowd alembic file?

• asset objects > load options tab > frame parameter
• default it $FF (frame number by default)
• clamp it by doing : clamp($FF, 1120, 1251)
• ie: clamp(val, min, max)
• 1120 is first frame of alembic, 1251 is last frame of alembic, the whole shot is 1120-1500

print screen

two kinds are different:

• computer screen
• remote screen

shadow pass maya vray

• ENV shadowReceiver
• CHR primaryVisibility 0
• TRACK_GEO remove
• matte surface check
• shadow check
• effect alpha check
• alpha contribution -1
• shadow tint color white
• reflect amount 0
• refraction amount 0
• gi amount 0

houdini light publish

• put light in subnetwork
• right click subnet
• choose otl asset publisher, create local
• library : library
• parent : light
• hda name : courtyard
• then otl asset publisher again, publish