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    ② Week 6


            Bulgari Serpenti Ring      


    Feedback from Mentors (Class 11 )

    FX & Camera
    Smooth out the strange beat in FX.
    Fix the camera hitch.
    Shot 2-1: Start tighter with subtle movement at the beginning.
    Shot 2-2: Smooth out the camera.

    Lighting & Lookdev
    Shot 3: Ensure proper lighting for the diamonds (key, rim).
    Check the reflection on the ring.
    Shot 3-1: Check for black spots on the ring.


    Composition & Art Direction
    Shot 3-1: Art direct Ky’s hat.
    Skip the rack focus for the mountain cards in 2-2/2-1.


    Color & Grading
    Improve the last shot’s color (reduce green/gold tone, warm it up).


    Technical Checks
    Check in Nuke for any geo issues.



    Week 6 Task
    1. Houdini Arnold rendering - fixing cryptomatte not displaying in nuke
    2. Shot1 Fx: Modify the model of the scales to more closely resemble the scales of real snakes
    3. Shot2 Fx & Anim: Modify the ring motion animation and modify the particle trail according to the new shot2 camera
    4. Shot3 Fx: color matching with backgroun and add some shinne particle 

    1. About Cryptomatte in Houdini Arnold

    Last week, I tried various ways to remove the motion blur on the moving ring, but Arnold doesn’t allow disabling motion blur for a single object while keeping it enabled globally. After discussing with Veronica (compositor), we decided to keep the Cryptomatte channel in the EXR, as it supports motion blur, transparency, and depth of field while creating ID mattes automatically.  But the crptomatte I exported from exr, in the nuke's cryptomatte node, the layer section is off.

    issue: single frame test: cryptomatte is not working in Nuke (nothing shows up in the layers section)



    Trouble shooting
    Houdini arnold user guide (cryptomatte) :https://help.autodesk.com/view/ARNOL/ENU/?guid=arnold_for_houdini_shaders_ah_Cryptomatte_html

    I guess two reasons: one is cryptomatte affected by object names, so they need follow the MtoA naming convention (based on arnold user guid). another is I shouldn't save the render result from houdini's renderview, cryptomatte might not work properly. in this way to ensure the data is saved correctly, it's better to render through batch render or render sequence to disk, instead of saving directly from renderview. and for more details on how to set up cryptomatte see the following slide images:

    1. In Houdini (shop level), Arnold Vopnet > Cryptomatte shader
    2. In houdini(out level), arnold rop > properties > output tab > add cryptomatte shader in AOV shaders
    3. set the cryptomatte naming attribute for the rendered object
    4. In nuke, cryptomatte node check (layer section part is working)
    5. In NUke, layer selection detail


    2. Shot 1: scale transformation Fx development

    Since the previous scale model was just a flake with basically no details other than the general shape, I modelled a new one in maya based on real snake scales and then gave it a double-sided material (jade and gold) in houdini

    real snake scale reference (source:https://en.wikipedia.org/wiki/Snake_scale#/media/File:Scales_of_Crotalus_molossus_ssp._nigrescens_(Viperidae).jpg)
    single scale modeling (modeling in Maya), with two side materials
    scale transformation fx (viewport in houdni)


    I changed from copy to point to instance because of the high number of faces in the new scale model, as well as the excessive number of scales that prevented arnold from rendering them

    scale fx (flipbook in houdini)
    change from copy to point to instance



    2. Shot 2: Ring animation &  snale shape  particle trail path

    This week's shot2, is mainly about modifying the camera movement (by Mia Esparragoza), I'm mainly responsible for modifying the ring animation and the particle trail path according to the new camera movement.

    Regarding the particle trail material, I wanted the trail to look shiny, so I added a glowing particle around the main trail, but I wasn't sure if it would look cluttered.

    ring animation & particle trial with new camera (flipbook in houdini, camera setting by Mia Esparragoza)
    render result (ring morphing fx by Soi Park; shader&camera by Mia Esparragoza; lighting by Zane Kidwell, ring anim& snake shape particle trail by Yilin Zhao)


    3. Shot3: abstract particle fx development

    Regarding the fx of shot3, the main thing is to change the colours, the previous colours were too green and not close to the background.


    Shot3 of week5 (shader&camera by Mia Esparragoza; lighting&MP by Zane Kidwell, Abstract particle by Yilin Zhao, Compositing by Veronica Ramirez)



    Firstly, I tried to match the background colour behind shot2, and also tried a few different warm tones because I was worried about it being too much like the colour of the sand, and finally, after a few compositing tests with Veronica, we ended up picking the 3rd of the compositing tests

    color test: matching shot2 background color (Redshift houdini render)
    color test: different warm color tests (Redshift houdini render)
    Compositing tests by  Veronica Ramire , (shader&camera by Mia Esparragoza; lighting&MP by Zane Kidwell, Abstract particle by Yilin Zhao, Compositing by Veronica Ramire) (Nuke and Houdini)

    Based on team members’s feeback, I added luminous flow particles to the surface

    week 6: shot3 final result (redshift houdini)



    Yilin Zhao / SANM560 / SCAD x Harbor