Q about the Soft Dots VEX node

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Hi!

What does the ‘Blur’ parameter do in Soft Dots VEX node? It doesn't seem to do anything.

Tested in H14.0.203.13 and H13.0.447
Attached file was made in H14

Cheers
-k

Attachments:
soft_dots.hipnc (209.7 KB)

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Hi,

It controls the blurriness of the map. You have to setup your material like this.

Attachments:
soft_dots_153.hipnc (408.1 KB)

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Thanks for the reply pusat.

It doesn't seem to do anything, not even in your file.

Now, i assume that if reduce the blur into 0, the edge between the white, the “mask” that Soft Dots will create, and the black color, should be straight, without any blur, and if i set it to high value, there should be a gradient from the center of the dot, to its “border”

And, yes, if your are creating “real” material, you need the surface model, but in my case i was just testing, and thats why the soft dots was connected directly to Cf.

-k

PS: here is two screenshot from my system, one with the low blur and one with the high value

Attachments:
10_blur.png (223.2 KB)
0_blur.png (226.9 KB)

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Yepp, it does nothing.
One can follow the trail.

The code on the node calls:

vop_StampPattern($layers, $dotsize, $dotrand, $blur, $ss*$sfreq - $soff, $srand, $tt*$tfreq - $toff, $trand, 1, 0, “bump”, $filter, $seed);

You can check the function in voplib.h, and it does use the blur(softness) to calculate the filter width:

du = vop_FilterWidth(px) * softness;
dv = vop_FilterWidth(py) * softness;
fwidth = max(du, dv);


But when it eventually calls vop_BumpStamp(fx, fy, fwidth, filter); You can see that the filter width is not actually used:

vop_BumpStamp(float px, py, fwidth; string filter)
{
float d = px*px + py*py;
return 1-smooth(0.0, 1.0, d);
}


To be fair, the vop_stampPattern() function is used by many of the other vop patterns as well, several of which actually use the blur value.
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Soo..its a bug?
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Yes

Not a bug in the sense that something is broken, they just seem to have the same vops interface for all the patterns that use the vop_StampPattern function, and have forgotten to remove the Blur input connector from those that do not actually use it in the code.

So, fire off a bug report!
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Ookoo, thx for the detailed info!

-k
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Houdini 14.0.263: The blur and filter paramters were removed from the softdots VOP since they were placebos and didn't actually affect the behaviour of the VOP.

\o/
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