nHair Passive Fill attribute ?

#1

I know where it is on the Create Hair options, but is there a way to adjust this value after the hair system is created? Can not seem to find this attribute in the nodes other than the follicles themselves.

The Passive Fill attribute determines the proportion of the follicles that are initially set to active versus passive. If the Passive Fill is 1, then every other row and column of follicles will be passive (with the points not in these rows or columns being dynamic). If it is 2 then there will be two rows/columns of passive for each row containing dynamic. The number of dynamic hairs goes down dramatically as the Passive Fill increases. If the motion of the hair is relatively uniform you might not see much difference when a large percentage of the hairs are passive. However the Passive Fill will be uniformly interpolated between the active hairs. This creates a uniform mass of hair, without requiring self collision.

Just curious if there is a master setting or do you have to use the spreadsheet to set the ratio manually?

Thanks.

#2

You can select follicles and make passive ones active or visa versa. However you may need to create a start position curve when making passive follicles active. You can do this by doing set startPosition from Current. As well you can add/delete passive (or active) follicles using follicle paint.

#3

Thanks Duncan!

I was looking for the same attribute that is on the hair creation dialog that allows you to set the Passive Fill value by entering 1, 2 etc.

Any chance of getting that added to the attributes in the interface so that you can adjust it"globally" in this same way after you create the hair?

#4

It doesn’t work as an attribute after the fact because the passive follicles are not computed on the fly but are actual dependency nodes created when you setup the hair system. If it was on an attribute then changing the value would need to create and delete nodes on the fly, which would cause all kinds of problems.

I don’t know if this helps, but if you have paint effects output then the hairs per clump might do something like what you are after if you make the clump width ramp constant and clumpInterpolation = 1.0. ( If you need output curves instead of pfx you could do convert pfx to curves on the hair system)

#5

Ah OK that explains it. It was not clear in the manual and I was searching for a while looking for it until I realized it was only on the creation panel.

Also I think I was looking for something else than what that does. And I think what you just said confirms that this is not what I was looking for.

I think my confusion lies in the fact that you have hairs per clump. And those to me look “passive” because they individually do not seem to be dynamic but follow the follicles.

So I think I get it now. Thanks.

#6

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