Vw2023 - Difference in Rendering of Window Glass between Redshift & Renderworks

[rDesign]

As a test I rendered a SLVP of a Renderworks Camera in both Redshift Exterior Fast and Renderworks, not changing any materials, only changing the Background Render style, and the windows in the Redshift version show much more refraction than in the Renderworks version. The roof beams are shown accurately in the Renderworks version, but in the Redshift version they have an unrealistic amount of refraction. The windows are standard Window PIOs.

 

(Note: to make sure it wasn't due to some low quality setting on the Redshift Exterior Fast, I also ran a Redshift Exterior Final version and got the same inaccurate results, just muuch more slooowly).

 

Edited November 3, 2022 by rDesign

[hannesduplessis]

Hi rDesign

 

I came across your post when I ran into a similar issue, except even more extreme.

 

I have a few render files set up for when I am trialling new machines, to see how they compare in terms of render speed. In one of the setups, the views is through a glazed sidelight into a room, and below is the result of those renders. Bear in mind that these are the same viewport, the only difference is the render style.

 

I do hope there is a solution to this, but for now I am staying away from Redshift.

 

Hannes

 

[BartH]

Check out this thread about Redshift Glass: I think the consensus is that Redshift calculated the index of refraction differently than Renderworks,

There are a couple of options listed as workarounds.

Ideally, we wouldn't have to recreate a texture to be Redshift specific, but that looks like the case with the glass shader. 

 

 

[rDesign]

@Dave Donley

 

Any update on this issue in Vw2025 Update 5? Not ideal to have two separate sets of transparent / glass textures for Redshift and RW. Thanks. 

Edited June 7, 2025 by rDesign

[Jesse Cogswell]

There also used to be an issue with using the Glass shader for reflection in Redshift.  I usually use Mirror instead when rendering in Redshift, though I haven't tried it in VW2025 yet.

[Elite Exhibits]

@Jesse Cogswell Your 2 cents on when to use RED SHIFT vs Shaded or RenderWorks ?

 

We find that RED SHIFT takes longer and adds little to the end result, compared to (v2024) Shaded, for example, ... reflections maybe though glass is uncommon for our workflow.

 

Thanks

 

Peter

[Jesse Cogswell]

@Elite Exhibits Generally, I like to stick to Renderworks as I find it a bit more consistent, but it largely depends on the lighting needs of the renderings.  Generally, I find Redshift to be a touch faster, and much faster if I need lit fog for a more theatrical touch, but Redshift doesn't work with lighting that has Use Emitter checked, which is how I dial in realistic intensity when I'm not using custom lights with IES distribution files like when I am using framing projectors and need to show shutter cuts or if I am using a fixture that doesn't have an IES file available.  In those cases, I have to use Renderworks.

 

I have also used Renderworks when I want to have finer control of environmental reflections.  I did some renderings where I was able to take an existing panorama photograph of the wider environment and applied it as the environmental reflections background so that it showed up on glossy surfaces, but was able to apply a separate matte gray background for the rendering so I could focus the rendering on the things that were actually important.  In Redshift, discrete environmental reflections aren't an option.  The downside of that particular rendering is that I needed lit fog for the fixtures as well, so I had a separate Redshift viewport that just did the lighting fixtures against a completely black background, then added it to the Renderworks rendering in Photoshop using it on a "Screen" layer.

 

I have run into issues with Renderworks where Vectorworks crashes on a viewport that has a lot of lighting fixtures in it, but renders fine on Redshift.  If I'm in that situation, I'll just use Redshift unless I have to use Renderworks for shutter cuts.  Then I'll just parse out the lights onto different layers so I can turn large swaths of them on a Viewport to Viewport basis depending on what the camera can see.

 

I do find it a bummer that I can't seem to batch render Redshift viewports.  If I grab a bunch of them and press Update, only the first one will actually render, the rest will just be white rectangles.  So while I find it generally faster, I do have to babysit the renderings and do them one at a time, which I really don't love.  With Renderworks viewports I can generally grab all of them, press Update, and go do something else and let them all render.

 

Personally, I almost never use Shaded for a rendering.  Reflections have gotten so much better, but I need to show realistic lighting and there just isn't a great way to do that in Shaded.