arnoldrenderer.com arnold support
  • Home
  • Anonymous
  • Sign in
  • Create
  • Ask a question
  • Spaces
  • C4DtoA
  • HtoA
  • KtoA
  • MtoA
  • MAXtoA
  • SItoA
  • Arnold Core Renderer
  • Arnold GPU Beta
  • Development
  • Shader Hacking
  • Help
  • Explore
  • Topics
  • Questions
  • Users
Skip to main content
  • Ask a question
    • C4DtoA
    • HtoA
    • KtoA
    • MtoA
    • MAXtoA
    • SItoA
    • Arnold Core Renderer
    • Arnold GPU Beta
    • Development
    • Shader Hacking
    • Default
    • Help
    • Topics
    • Questions
    • Users
  • Sign in
  • Home
  • Arnold Core Renderer
question
EVAN SMYTH avatar image
EVAN SMYTH asked · Apr 12, 2018 at 09:28 PM

Z-values not written for low alpha values (<0.15) - i.e. near boundaries

In mtoa, using the closest filter for a Z AOV, I find that Z values are only written for alpha values above some threshold (about 0.15) which makes sense in a general scene with lots of overlapping stuff. In my case I am solo rendering objects and need Z values for any pixel that has non-0 alpha and I am doing a sort of back to front "over" composite in post. I can dilate my depth buffer for each "layer" with some simple extrapolation logic but am wondering if there is a built-in way of achieving this within the Arnold -- where the ground truth information is available and be dropped as I understand it.

First of all, is my understanding correct that there is such a threshold? And secondly, is there a way of controlling this threshold? I ask all of this because it is possible that my z-values are bucketing but my z-range is reasonably tight (about 0-215 and then normalized) and I'm using 32-bit floating point values to represent the depth. Also, I see depth values that are 0.00025 different from the one in question so I do seem to have the z resolution. I feel pretty confident that I have enough depth resolution so am looking at this as a threshold issue.

mtoaalpha for geometryz-depth
Comment

People who like this

0 0
10 |600 characters needed characters left characters exceeded
  • Viewable by all users
  • Viewable by moderators
  • Viewable by moderators and the original poster
  • Advanced visibility
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

0 Answers · Write an Answer
Write an Answer
Hint: Notify or tag a user in this post by typing @username.

Up to 5 attachments (including images) can be used with a maximum of 2.0 MiB each and 9.8 MiB total.

Welcome to the Arnold Answers community.

This is the place for Arnold renderer users everywhere to ask and answer rendering questions, and share knowledge about using Arnold, Arnold plugins, workflows and developing tools with Arnold.

If you are a new user to Arnold Answers, please first check out our FAQ and User Guide for more information.

When posting questions, please be sure to select the appropriate Space for your Arnold plugin and include the plugin version you are using.

Please include images, scene and log files whenever possible as this helps the community answer your questions.

Instructions for generating full verbosity log files are available for MtoA, MaxtoA, C4DtoA, HtoA, KtoA, and Kick.

If you are looking for Arnold Documentation and Support please visit the Arnold Support site.

To try Arnold please visit the Arnold Trial page.

Bottom No panel present for this section.

question details

2 People are following this question.

EVAN SMYTH avatar image Satish Goda avatar image
Answers Subscribe to Answers Answers and Comments Subscribe to Comments and Answers

Related Questions

deepexr append error 3 Answers

How to download and install Arnold for Maya 2016 ?I can found MTOA files that fits 2016 version.However,I am wondering where to get Arnold files itself 0 Answers

AiOpSetTarget not working 0 Answers

© 2009 - 2019 Solid Angle S.L. All Rights Reserved
website terms /  privacy policy / contact