Bezier spline in Substance Painter for something like stitches brush?

gnoop · Nov 2021

Does anyone know a working solution ? 3d party maybe? Maybe a spline guide approach like in Zbrush or 3d coat?. I mean to paint a rope for example ?

Also can SPainter use a long pattern image for such a brush rolling out alone a brush stroke also like Zbrush or 3dcoat or Corel PAinter or it always should be square?

poopipe · Nov 2021

there's a number of tools available that use fx-maps if you have a google.
eg. this (not particularly a recommendation, just the first one i remember seeing)
https://www.artstation.com/artwork/9dk2o

not sure if there's a good pixel processor version released but it's not exactly rocket science (a bezier curve is just a stack of lerps) - if you're interested i've got a simple sd-sex implementation you're welcome to have the code for

painter brushes can be any aspect ratio but at least on the pre-green versions you are limited to stamping your alpha at set distances along the stroke (as per photoshop) and there's no way to access the brushes through the javascript API
short answer - dont think it's possible

gnoop · Nov 2021

Thanks poopipe Please , share a link to your simple implementation. I never managed to figure out how people do it. Prefer to understand it myself first.

As of rolling out brush my hope we can have a uv stripe follow a bezier curve through a pixel processor or fx map. It could be used to map anything along and scale the tiling.

poopipe · Nov 2021

that second bit is definitely not straightforward in a pixel processor - if it's actually practical at all

however ,

this sd-sex expression will plot <n> points a bezier defined by 4 control points.

<p># points
p0 = float2(0.2, 0.2)
p1 = float2(0.8, 0.2)
p2 = float2(0.4, 0.8)
p3 = float2(0.8, 0.8)
pos = get_float2('$pos')
y = sqrt(2.0)

::for i in range(5)
    delta = 0.25    
    t = delta * {{i|float}}

    # position on curve
    p = p0 * vector2((oneminus(t)*oneminus(t)) * oneminus(t),(oneminus(t)*oneminus(t)) * oneminus(t)) + p1 * float2(3.0,3.0) * vector2(t * (oneminus(t) * oneminus(t)),t * (oneminus(t) * oneminus(t))) + p2 * float2(3.0,3.0) * vector2((t*t) * oneminus(t),(t*t) * oneminus(t)) + p3 * vector2((t*t) * t,(t*t) * t)

    y = min(y, distance_vec2(pos, p))
::endfor

_OUT_ = y <br></p>

this will plot 5 points, afaik you can't use a variable to define the length of a loop in this

if you add more points you get a smoother curve - delta should = 1/(numberofpoints-1)

there is a simpler to understand method of implementing a bezier by stacking lerps but you can google for that (coding train has a nice video)

you need sd-sex installed, which is here....

https://github.com/igor-elovikov/sd-sex

it will change your life

gnoop · Nov 2021

Thank you poopipe

Bezier spline in Substance Painter for something like stitches brush?

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