Cineversity

Hello, how can I render only the reflection using the physical renderer?

I rendered my file using the standard renderer, it’s fast and provides a fine result except the reflection. I tried the physical renderer and it has a better reflection result but it’s slower. I want to composite the physical reflection with the standard result.

Please note that I don’t want to use ProRender.

I tried to save only the multi pass files of material reflection, I chose TIF format, but the files I got isn’t TIF, it’s just “file”.

I recorded: https://youtu.be/E1ZHMjDeUcs

Edit: the problem is the shadow quality, not the reflection. But I still want to report the bug I recorded.

Hi huanle5062,

It is not a bug. If you find a code-based problem in the application, then that is a case for the support:
https://www.maxon.net/en/support-center
My part is educational only, I do not code, not do technical support based on “bugs”.

Several passes relate to the Reflection.
https://help.maxon.net/us/index.html#DRENDERSETTINGS-RDATA_GROUP_MULTIPASS

As a rule of thumb, if there is a Material in the pass name, then it most likely will present the information of the material, like the color/brightens that would influence the amount of reflectiveness. Not the reflection by itself.
If you compare this with the Reflection pass, you will see that this pass provides anything reflected on that surface that holds the material.
Example:https://www.amazon.com/clouddrive/share/l68rC0JeHITzQuh3h2Fhno08ZViMtN24ciQxhYI7wbl

My suggestion, call up all passes and render them all in a PSD file, then you have an excellent catalog about what each pass holds in terms of information.

The shadow problem that can be a wide field. It is based on the light source (Soft, or shadow-maps) should be avoided, if my opinion counts. Area Shadows can cause problems if the sampling is too low, etc.
In the manual link above, scroll down to the shadow part, there is an option to fix some problems.

I assume you know that, but I write in a forum: To do multi-passes in 8bit/channel and sRGB is undoubtedly not a good idea. Use Open EXR and linear, especially when it comes to shadows. I assume the 8bit/cannel file in the video was a quick test. Which limits the usability of the examination from the start. As a side note, even if the Production is even these days in REC709, sRGB has a different definition. You can set up Color Profiles if needed, but I encourage you to work only in Linear when it comes to Multi-pass and Compositing.

Again, shadows can be an extended theme, if no project file is provided. I think that guessing around is a waste of your time, and professional.

I’m happy to look into it if you have a reduced scene that shows that problem.

All the best

Dr. Sassi - 27 April 2020 03:53 PM

Hi huanle5062,

It is not a bug. If you find a code-based problem in the application, then that is a case for the support:
https://www.maxon.net/en/support-center
My part is educational only, I do not code, not do technical support based on “bugs”.

Several passes relate to the Reflection.
https://help.maxon.net/us/index.html#DRENDERSETTINGS-RDATA_GROUP_MULTIPASS

As a rule of thumb, if there is a Material in the pass name, then it most likely will present the information of the material, like the color/brightens that would influence the amount of reflectiveness. Not the reflection by itself.
If you compare this with the Reflection pass, you will see that this pass provides anything reflected on that surface that holds the material.
Example:https://www.amazon.com/clouddrive/share/l68rC0JeHITzQuh3h2Fhno08ZViMtN24ciQxhYI7wbl

My suggestion, call up all passes and render them all in a PSD file, then you have an excellent catalog about what each pass holds in terms of information.

The shadow problem that can be a wide field. It is based on the light source (Soft, or shadow-maps) should be avoided, if my opinion counts. Area Shadows can cause problems if the sampling is too low, etc.
In the manual link above, scroll down to the shadow part, there is an option to fix some problems.

I assume you know that, but I write in a forum: To do multi-passes in 8bit/channel and sRGB is undoubtedly not a good idea. Use Open EXR and linear, especially when it comes to shadows. I assume the 8bit/cannel file in the video was a quick test. Which limits the usability of the examination from the start. As a side note, even if the Production is even these days in REC709, sRGB has a different definition. You can set up Color Profiles if needed, but I encourage you to work only in Linear when it comes to Multi-pass and Compositing.

Again, shadows can be an extended theme, if no project file is provided. I think that guessing around is a waste of your time, and professional.

I’m happy to look into it if you have a reduced scene that shows that problem.

All the best

Thank you for your reply! I fixed my shadow by increasing the shadow map. The thing I learned here that before I render the final result, I shall test render every corner of the project to see if there is any problem.

Thanks for the reply, huanle5062.

With a project file, I would have been able to point to that.

Please note that the Shadowmap (Soft) is a probe-based approach, and has nothing to do with realistic shadows. I think I warn everyone, for way over a decade by now, to use it. Which is often ignored because it is fast.

It’s a relic from a time when CPUs were measured in MHz rather than in the GHz.
In short: after a specific distance, the questions is, is this in front or behind an object. (From the POV [point of view] of the light source.)

Those raster-points are then applied to bright and dark, and between the raster points, it is just simply interpolated. Hence the softness. For stills that might work, even it has that early ‘90s aesthetic.

Anyway, in the moment animation is involved, chances are that an object moves before, perhaps on it, then behind that point of exploration. Flickering is the result. There is more. But I guess you know already that you have to have an eye on that.

All the best