Hello,

I want to make hair. I made a sphere , birth particles and copied a curve on the particles via a Copy SOP.

I got the following problems:

1/my haircurves are not staying up on the sphere. (they don't follow the normals)

2/ the haircurves, when rendered, are very big, how do I get them thinner?

3/ when I comb the normals with a Comb SOP, this don't seems to work; How do you use the Comb SOP (how can you visualize the normals so you can see the real combing?)

many thanks,


bernard

bernard

Hello,

It might be better and faster if you use Scatter SOP instead of POP to populate static points on your geometry for hair. Just a little tip. : )


1) Have you make sure that the root of your hair curves are sitting at position 0,0,0 so that you can properly get the hair root to sit on those points which are copied (the follicle)? Another thing you might like to check is to make sure that each of those point has an Up Vector (an attribute called “up”). Usually, you need at least 2 vectors in order to get a proper orientation.

2) Make sure that you have an attribute called “width”. You can use Attribute Create SOP to make this attribute. (Although I've been told ‘pscale’ works for Mantra, too… not sure…)

3) Did you make sure that you turned on the “Point Normal”? If you use the POP to scatter points on the surface of a geometry, I don't think it inherited the surface normal unless you make your collision POP to pick up surface normal. If you use Scatter SOP, this may not be too big of a problem as the Scatter SOP will pick up and interpolate the point normals accordingly. However, I believe you may need to create the point normal (Point SOP, Facet SOP, AttribCreate SOP) before you use Scatter SOP to pick them up. Another thing you want to watch out for is that Comb SOP does not work on just those scattered points… At least I don't think so, if my memory is correct… The way you may want to do this is to make sure your geometry is sufficiently subdivided, and then use the Comb SOP to comb your point normals. Once this is done, run append a Scatter SOP afterward and it should work well.


Hope this helped.
Alex

Hello TheUsualAlex,



thanks for the info, where can I turn on the “Point Normal” and how can I create the point normal ( do I have to use all 3: Point SOP, Facet SOP and AttribCreate SOP)?

Many thanks


bernard

Bernard
thanks for the info, where can I turn on the “Point Normal” and how can I create the point normal ( do I have to use all 3: Point SOP, Facet SOP and AttribCreate SOP)?

Oops… My apologies for the vagueness of that one.. What I meant to say is “turn on the ”Point Normal“ display so that you can see it in viewport (assuming that you have point normal set for each points, of course). To display point normal, you can click on the point normal button to the right of your viewport (3rd button down).

Now, to set the point normal, you can use Point, Facet, or AttribCreate SOP. For Point SOP, just change the ”Keep Normal“ to ”Add Normal“. Both Point SOP or AttribCreate SOP will allow much finer control of how the point normals should be. For Facet SOP, check on ”Pre-Compute Normals".

hope this clarifies a bit…


Alex

OK thanks,

I've use a Facet SOP and it works great. To scale the line width , I add a AttribCreate SOP . I put width in variable, what must I do further to set my line width?


Many thanks


bernard

Hi,

Change the name from “attribute1” to “width”, and then play with the first “Value” field. That should do it.


-Alex

Hello Alex,


Do you have any tips to color my hair ( hair shader ?)

thanks,


bernard

if you look under “shops” there is a shader called VEX_Hair,which is a good starting point.

Hello,

I applied the VEX Hair Shader to my copied hair curves , but I don't get good results. What do they mean by “the curves can be shaded like tubes if applying the Vex Hair shader”. I don't get tubes.

I've done a simple test: draw a line, append a shader sop . When I render this line the shading is 90 degrees turned (vex hair shader)

On some places of the curves the highlights are too strong (full white).
Maybe it has to do with the light setup? .. I don't know. Any help is more than welcome.


Thanks,


bernard

I can't get the tubular effect as well with the curve rendering (via VEx Hair shader). only the standard ribbon curves…

I think you might be better of using Arno's hair shader.. You can find it here:
http://odforce.net/forum/index.php?showtopic=2208&st=96 [odforce.net]

Thanks Alex


bernard

I think the standard VEX Hair shader has long been regarded as “in disrepair”.