Custom coverage color transparency value

[Matt__W]

I'd like to create a custom transparent color for a coverage area. What I'm looking for is something similar to the INDUSTRIAL coverage style but a bit less transparent. How do I know what the alpha channel value should be if I want to achieve a 25%, 50% or some other percentage of transparency of any particular color? Is there a rule of thumb or a formula?

[elliott.rosenfeld · Accepted solution]

Hi Matt,

So it looks like the Industrial coverage style is using Black Alpha50 for the fill style, which I assume means it's black with 50% transparency.

To test that out, I selected the colors tab, chose black, and then reduced the alpha value in half (from 255, the default alpha value for 0% transparency, to 123), and pressed OK.

When I compare the previews (make sure to "Reset Preview" each time) of the default "Black Alpha 50" material fill color to the "x0000007B" Color that I just created using Black and Alpha value of 123, they look the same.

Default "Black Alpha 50":

New Color with Black and "123" for alpha value:

So, now to reduce the transparency even more. Say that I want to see if I can get roughyl 25% opacity, rather than the about %50 opacity this style is currently using, I reduce the Alpha value even more (from 123 to 61). AS you can see below, it looks like that did the trick. SOoo, apparently in InfraWorks 360, the alpha value for 0% transparency is 255, while 50% transparency is about 123, and 25% is about 61.

Just for kicks, I reduced the Alpha value to 1 to see what would happen:

This time, the preview does not seem to show full opacity:

However, when I sketch this coverage style, it does appear to have full transparency (it's a little bit lighter than the terrain in this second image because my mouse cursor is highlighting the coverage as I hover over it):

Hope this helps!

Best,

Elliott

[Matt__W]

That was just WAAAY to easy. I figured it would be more complicated than that.

Thanks, Elliott.