Best way to sample noise
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On 15/05/2014 at 01:47, xxxxxxxx wrote:
What is the best way to sample noise (2D or 3D)?
E.g. I have NOISE_NOISE as noise.
What is the width and height of the noise.
What is the size of equal colored planes?Which setting to use when sampling. For x in range(300) and then?
r = p.Noise(noisetype, False, c4d.Vector(x, x, x))Doing so, I do get various values, but I cannot link them to a point on the noise map.
Also, when using noisetype = c4d.NOISE_NONE I get only 0.
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On 15/05/2014 at 04:30, xxxxxxxx wrote:
There is a verry nice example in the docs.
width = 300 height = 300 noisetype = c4d.NOISE_MOD_NOISE bmp = bitmaps.BaseBitmap() bmp.Init(width, height, 24) # Create and initialize the noise instance p = C4DNoise(1234) p.InitFbm(21, 2.1, 0.5) rw = float(width-1) rh = float(height-1) # Iterate through the bitmap and set the noise value per pixel for x in xrange(width) : for y in xrange(height) : r = p.Noise(noisetype, False, c4d.Vector(x/rw, y/rh, 0) * 7.0, octaves=5) o = int(255.0*r) if o < 0: o = 0 elif o > 255: o = 255 bmp[x, y] = (o, o, o) bitmaps.ShowBitmap(bmp)width and hight depends on the bitmap size
like
bmp = bitmaps.BaseBitmap()
bmp.Init(width, height, 24)the size of colored planes is in this case:
r = p.Noise(noisetype, False, c4d.Vector(x/rw, y/rh, 0) * 7.0, octaves=0)
size = width/7.0I did not understand
link them to a point on the noise map
Martin
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On 15/05/2014 at 05:13, xxxxxxxx wrote:
If you want to read a noise
It´s always relativ to the given global scale and not a bitmap size.mat=doc.GetFirstMaterial() shader=mat[c4d.MATERIAL_COLOR_SHADER] print shader glbsize=shader[c4d.SLA_NOISE_GLOBAL_SCALE] size=shader[c4d.SLA_NOISE_SCALE] print size print glbsize print glbsize*5/size[0], "the size of colored planes relativ to the global scale" -
On 15/05/2014 at 06:02, xxxxxxxx wrote:
Yes, I saw the example, but I want to deform an object using a noise.
How to map the noise to the object? -
On 15/05/2014 at 08:07, xxxxxxxx wrote:
That's a question of how you want to map the noise to an object. For instance, you could use
the UV position of its points to pass to the noise function and move the point along its vertex
normal.-Niklas
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On 16/05/2014 at 01:17, xxxxxxxx wrote:
Ok, so use the UV coordinates to get the noise value?
r = p.Noise(noisetype, False, UV coordinates )Why should you move the point along it vertex normal.
Isn't it enough to just get the noise for UV points and use that value to for example size the corresponding polygon? -
On 16/05/2014 at 03:42, xxxxxxxx wrote:
Thanks Niklas,
could you please tell us how to get the specific color vlaue of the calculated uvw position?.
I´m at this point right now:import c4d def main() : #Get shader mat= doc.GetFirstMaterial() shader= mat[c4d.MATERIAL_COLOR_SHADER] print shader noisetype= shader[c4d.SLA_NOISE_NOISE] print noisetype #Get tag UVWTag= op.GetTag(c4d.Tuvw) print UVWTag #just test it for one polygon for i in xrange(UVWTag.GetDataCount()-1,UVWTag.GetDataCount()) : uvwdict= UVWTag.GetSlow(i) #corresponding Polygon corres= op.GetPolygon(i) #select for testing Polygons= op.GetPolygonS() Polygons.Select(i) print corres p1= op.GetPoint(corres.a) p2= op.GetPoint(corres.b) p3= op.GetPoint(corres.c) p4= op.GetPoint(corres.d) #calculate the vertexnormals of the corresponding vertices dif_p1= p1- p2 nor_p1= p1.Cross(dif_p1).GetNormalized() print nor_p1,"nor_p1" dif_p2= p2- p3 nor_p2= p2.Cross(dif_p2).GetNormalized() print nor_p2,"nor_p2" #if tris if corres.d== corres.c: dif_p3= p3- p1 nor_p3= p3.Cross(dif_p3).GetNormalized() print nor_p3,"nor_p3" #if quad else: dif_p3= p3- p4 nor_p3= p3.Cross(dif_p3).GetNormalized() print nor_p3,"nor_p3" dif_p4= p4- p1 nor_p4= p4.Cross(dif_p4).GetNormalized() print nor_p4,"nor_p4" #Values of UVW_Coordinates print uvwdict["a"],"a" print uvwdict["b"],"b" print uvwdict["c"],"c" print uvwdict["d"],"d"Martin
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On 30/05/2014 at 01:59, xxxxxxxx wrote:
I´m not sure if there is a better solution to handle noise sampling, but
with channel data from the render module you can read the overall shader information.And of course, sorry for the twaddle I posted before.
A vertex normal could be calculated like this:Cheers
Martinimport c4d from c4d import utils,Vector from c4d.utils import SendModelingCommand def main() : if op== None: return #convert clone= SendModelingCommand(command= c4d.MCOMMAND_CURRENTSTATETOOBJECT, list= [op.GetClone()], doc= doc) if not clone : return obj= clone[0] #optimize opti= c4d.BaseContainer() opti[c4d.MDATA_OPTIMIZE_POINTS] = True SendModelingCommand(command= c4d.MCOMMAND_OPTIMIZE, list= [obj], bc= opti, doc= doc) #triangulate the clone to ensure correct results with nonplanar quads SendModelingCommand(command= c4d.MCOMMAND_TRIANGULATE, list= [obj], doc= doc) #init neighbor class and get obj properties PointCount= obj.GetPointCount() PolyCount= obj.GetPolygonCount() Matr= obj.GetMg() nbr= utils.Neighbor() nbr.Init(obj) #set an empty list for the face normals Face_N= [] #calculate face normals for i in xrange(PolyCount) : poly= obj.GetPolygon(i) p1= obj.GetPoint(poly.a)+Matr.off p2= obj.GetPoint(poly.b)+Matr.off p3= obj.GetPoint(poly.c)+Matr.off dif_p1= p1- p2 dif_p2= p2- p3 normal= dif_p1.Cross(dif_p2).GetNormalized() Face_N.append((normal,i)) #for testing facenormals, calculate a matrix, test it with small cubes mid_p= (p1+p2+p3)/3 off= mid_p v3= normal if abs(normal*Vector(0,1,0))<0.9999: v2= normal.Cross(Vector(0,1,0)).GetNormalized() else: v2= normal.Cross(Vector(1,0,0)).GetNormalized() v1= normal.Cross(v2).GetNormalized() Face_N_Matr= c4d.Matrix(off, v1, v2, v3) cube= c4d.BaseObject(c4d.Ocube) cube.SetMg(Face_N_Matr) cube.SetAbsScale(c4d.Vector(0.1,0.1,0.1)) doc.InsertObject(cube) #set an empty vertex normal vector Vert_N= Vector(0,0,0) #for every point, average the neighboring facenormals to get the vertexnormal for i in xrange(PointCount) : Polys_P= nbr.GetPointPolys(i) for p in Polys_P: Vert_N+= Face_N[p][0] print Face_N[p][0] average= Vert_N/len(Polys_P) #reset the vertex normal vector for the next point Vert_N= Vector(0,0,0) #calculate a matrix, test it with small cubes off= obj.GetPoint(i) v3= average if abs(average*Vector(0,1,0))<0.9999: v2= average.Cross(Vector(0,1,0)).GetNormalized() else: v2= average.Cross(Vector(1,0,0)).GetNormalized() v1= average.Cross(v2).GetNormalized() Vert_M= c4d.Matrix(off+Matr.off, v1, v2, v3) cube= c4d.BaseObject(c4d.Ocube) cube.SetMg(Vert_M) cube.SetAbsScale(c4d.Vector(0.1,0.1,0.1)) doc.InsertObject(cube) c4d.EventAdd() if __name__=='__main__': main()