Dimming Not Working At Prop as Expected

[kev]

I have simple dimming for some props by using the Pulse effect that looks great in the Preview window but is hardly working on the actual lights. I am suspecting that it is a combination of the dimming curve adjustment coming from Vixen and the ESPixelstick Device Settings Brightness value.

I have set the ESPixelstick value for Device/Brightness to 0.35 and 0.5 but it exhibits the same lack of dimming steps.

I am also using the Enable Compression checkbox when exporting the sequence to FPP (.fseq file). Could this limit the dimming steps?

Vixen 36u4 Build 937
FPP v3.4.2-5-geed5aa47 (v3.4 branch)

[MartinMueller2003]

I have simple dimming for some props by using the Pulse effect that looks great in the Preview window but is hardly working on the actual lights. I am suspecting that it is a combination of the dimming curve adjustment coming from Vixen and the ESPixelstick Device Settings Brightness value.

I have set the ESPixelstick value for Device/Brightness to 0.35 and 0.5 but it exhibits the same lack of dimming steps.

I am also using the Enable Compression checkbox when exporting the sequence to FPP (.fseq file). Could this limit the dimming steps?

Vixen 36u4 Build 937
FPP v3.4.2-5-geed5aa47 (v3.4 branch)

Compression has no effect on output values. You are setting dimming in two places. Either do it in the curve or do it on the ESP. The ESP multiplies any value you send it by the brightness. That means your steps get reduced by the same percentage.

[kev]

Well that is what I suspect but leaving the brightness at 100% is way to much light. And if I use a master dimming curve in Vixen (or an Intensity layer) won't I get the same problem?

[TomL8345]

Kev,

What kind of lights are you using? Pixels, LED strings, something else? One thing I found is that the apparent brightness of LEDs is NOT linear. The difference in apparent brightness @ 50% and 100% are very close, most of the apparent dimming will happen between 10-50% on the LED strings I have tested

[kev]

Using pixels that are not dimming like I expect. I will be trying different settings to see if I can improve.

[MrDudeMan]

yeah you need a gamma correction curve/table made for pixels..

there was one posted here a few years ago

i wish the search features were better on this site

[jeffu231]

You can build gamma curves in the Vixen dimming curve as part of the patching chain. You want something that looks like the following.

ResultGammaFunction.PNG

There is a generator function in the Curve editor to build them for you with the f(x) Curve button. It brings up the following.


SetGammaFunction.PNG

Using the function example, you can replace the 100 with the max brightness you want. So if you want them to be 50% at max you would change the 100 to 50. 2.8 is the gamma value. Generally around 2.0 - 2.4 is a good general value. You can experiment here unless you happen to have pixels that you know what the best value would be. Once you click Generate, it will draw the curve for you. Save that as a library curve and use it when you add a dimming curve to the patching. A dimming curve in the patching is the best way to influence the overall brightness response of your lights. Then you don't need think about that when you sequence. Some of the controllers support this notion as well, so you could do it there as well, but you should only do it in one or the other place as previous posts have indicated.

[kev]

I think that I am misunderstanding how the dimming curves function.

What does the default dimming curve look like? 0 to 60 ?

What I did this year was create a Master Dimming Curve for each Group of props. For example, for my Eaves I have a dimming curve called Eaves Master. I set it for 100 to 100 thinking that if I needed to reduce the brightness of just the eaves that I could adjust just the one dimming curve. But is that curve holding the brightness at 100 all of the time?

[jeffu231]

The default curve should look like a / with the left at 0,0 and the right at 100,100. A flat curve will level all values in to whatever value out the flat line is at. It is a mapping lookup. It translates the incoming value along the bottom up to where the curve is and that is the outgoing value. The default / is linear where the value in is the value out or no dimming. To do just simple dimming you would alter the / to be lower at the far right. For 80% brightness the left value will be zero angling up to 80 on the far right. When you add gamma to it, the bend in the curve more aggressively dims the middle values to make it look more linear to the human eye.

[kev]

Thanks Jeff. I am sure that is where I messed up. I made all of the Master dimming curves 0,100 - 100,100 or always at 100. I have updated the curves by selecting my ALL group and adjusting the curve to 0,0 - 100,100 and the interfcace reported back that 3300 curves were modified.

Also, when my show started tonight, I was watching and did notice good smooth dimming on the xLights files while the Vixen files were not dimming as expected. I will export all of my Vixen sequences again with the new dimming and see how they perform.