Gaussian Blur values/radius in TVPaint - what is it ?

[D.T. Nethery]

I'm trying to coordinate with an art director who is doing his work in Photoshop because that's what he is used to , and I'm doing my work in TVPaint, following the style he is setting. In the scenes we are coordinating we have several effects layers that have Gaussian Blur applied .

When applying the Gaussian Blur FX in TVPaint what do the numerical values in the Width and Height box represent ? I had thought that the values were in Pixels , but I notice that if I blur something in TVPaint with a value of 25 , in Photoshop a blur value of 25 is MUCH more blurred than in TVPaint . In Photoshop a Gaussian Blur value of 10 is similar to Gaussian Blur of 25 in TVPaint . So what do the values in TVPaint represent if not pixels ? (and if they are pixels then why does blurring with a value of 25 in TVPaint look much less blurred than using a value of 25 pixels in Photoshop ?)

TVPaint and Photoshop Gausian Blur Values.png (80.05 KiB) Viewed 16835 times

[slowtiger]

Just tested.
PS 5 ≅ TVP 15
PS 10 = TVP 30.

[D.T. Nethery]

Just tested.
PS 5 ≅ TVP 15
PS 10 = TVP 30.

Thank you for confirming , Slowtiger . I was just about to post that I tried comparing PS and TVP side by side and it appears to me that a Blur Value of "25" in PS is equivalent to a Blur Value of "75" in TVPaint , so that is the same as your findings: PS is 1/3rd the blur value of TVP to get the same blur effect.

I'm still curious to know exactly what do the values in the TVPaint Gaussian Blur represent , if not 1-to-1 pixels ? Why are the blur values in TVPaint 3x the pixel value
of the same amount of blur in Photoshop ? I would imagine that is somewhat confusing to other users , too .

[NathanOtano]

This is called precision guys <3 cause TVPaint is the most professional

Well, maybe it's about the algorythm that is different?

[D.T. Nethery]

Well, maybe it's about the algorythm that is different?

Ok, yes, I get that , that's fine , but I would hope this is something that someone from the TVPaint Dev. team could jump in to explain, how the Gaussian Blur values are expressed in TVPaint ... (?) .

Most graphics/animation programs that I'm familiar with (Photoshop , ArtRage, Toonboom) use Gaussian Blur values in Pixels . TVPaint is different ... ok, I get that . In many functions TVPaint is different and I don't worry about it (because I absolutely ADORE TVPaint, please let me emphasize that ) , but in TVPaint it's a bit confusing because some FX Stack values ARE expressed in Pixels (such as Erode or Border or Toon Shading) so why is Gaussian Blur different ? Why doesn't the User Manual say anything about it , like : " Please be advised that the Gaussian Blur value in TVPaint is 3x the Gaussian Blur value in well-known applications like Photoshop " . ) This wasn't a huge issue for the production I'm currently working on , it only cost a couple of hours or so of research to figure out that Gaussian Blur in Photoshop is 1/3rd the value of Gaussian Blur in TVPaint , but does this really need to be so different ?

[Elodie]

Thank you David for the feedback.

FX like blurs have been added +15 years ago, so we have to dive into the code to know why it is different from Photoshop or other software (Adobe is the biggest, but they can also do mistakes ). First, I can notice that Photoshop and TVPaint do not have the same options for the gaussian blur : TVPaint offers a height / width option, whereas Photoshop just a unique "radius" to change
But to be honest, I don't think it is "confusing" other people, for most of the time they won't compare both FX between TVPaint and Photoshop : they will just play with the values, watch the result and apply it when they are satisfied. =)

[slowtiger]

I see that TVP doesn't give units for the blur values, so we only assume it's pixels, which would make the most sense. May I propose to check input fields for FX to see where a pixel value makes sense, and change this for a future version? Input needs to accept sub-pixels then, of course (like 0,8).