Hello
May I have a few suggestions about Parting Line feature in Fur.
First, per-point “Parting Radius” attribute on the “Parting Line” curve itself.
Because now it's a bit trcky to fade out partings.
Or maybe there is another way to do that.
Second, ability to override Parting Radius in cvex shader.
So, if you define a set from hairs id , you can assign custom influence of Parting Radius for those set.
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Technical Discussion » Parting Line
- archie
- 71 posts
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Technical Discussion » How to create LUT file?
- archie
- 71 posts
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Technical Discussion » How to create LUT file?
- archie
- 71 posts
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Hi Jacob,
There are 3 channels (RGB) in my header and I've created a table of values for each of them. As to docs, there must be more than 2 such values. And their overall number is limited by author imagination only.
Using 10.0.295 and will try a latest one soon.
But I think there is an error somewhere in my code, it would be so great to see a working example of LUT file for 1D LUT in text file format.
There are 3 channels (RGB) in my header and I've created a table of values for each of them. As to docs, there must be more than 2 such values. And their overall number is limited by author imagination only.
Using 10.0.295 and will try a latest one soon.
But I think there is an error somewhere in my code, it would be so great to see a working example of LUT file for 1D LUT in text file format.
Technical Discussion » How to create LUT file?
- archie
- 71 posts
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Hello. I can't create LUT file. Just following the docs explanation from $HFS/toolkit/html/image/lut.html. Using simple table of values, just to see if it works.
Unfortunately, getting the same error every time: “LUT failed to load”. But cannot understand where is the error.
Here is my code:
Version 1
Format any
Type RGB
From 0 1
To 0 1
Black 0
White 1
Length 4
LUT:
R {
0
0.25
0.5
1
}
G {
0
0.25
0.5
1
}
B {
0
0.25
0.5
1
}
Unfortunately, getting the same error every time: “LUT failed to load”. But cannot understand where is the error.
Here is my code:
Version 1
Format any
Type RGB
From 0 1
To 0 1
Black 0
White 1
Length 4
LUT:
R {
0
0.25
0.5
1
}
G {
0
0.25
0.5
1
}
B {
0
0.25
0.5
1
}
Technical Discussion » Shading Property overrides
- archie
- 71 posts
- Offline
Hi,
I want to know whether its possible or not to edit parameters creation menu , for example add some entries or edit existing ones. I.e. find out whether “Create All Local Material Parameters” (or any other) is a built-in command or external script which can be edited.
I want to know whether its possible or not to edit parameters creation menu , for example add some entries or edit existing ones. I.e. find out whether “Create All Local Material Parameters” (or any other) is a built-in command or external script which can be edited.
Technical Discussion » Shading Property overrides
- archie
- 71 posts
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Hi,
Is there a way to correct and add functionality to standard possibilities “Shading Property overrides” (http://img150.imageshack.us/img150/3883/paramu.jpg [img150.imageshack.us])which are accessible at the geometry level?
Is there a way to correct and add functionality to standard possibilities “Shading Property overrides” (http://img150.imageshack.us/img150/3883/paramu.jpg [img150.imageshack.us])which are accessible at the geometry level?
Technical Discussion » Problems with the "ramp" parameter
- archie
- 71 posts
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Hi!
I understand that “ramp” parameter is compound thus one is pretty complex. Its workflow slightly differs from other parameters workflow, for example you can not connect few “ramps” with expression. This parameter can be installed only from another node. Certainly it imposes restrictions on work with it.
But today I have found serious enough error. At creation of local parameters of any material on the geometry, “ramp” parameter is not overriden by them (http://img230.imageshack.us/img230/2916/rampz.jpg [img230.imageshack.us]).
I understand that “ramp” parameter is compound thus one is pretty complex. Its workflow slightly differs from other parameters workflow, for example you can not connect few “ramps” with expression. This parameter can be installed only from another node. Certainly it imposes restrictions on work with it.
But today I have found serious enough error. At creation of local parameters of any material on the geometry, “ramp” parameter is not overriden by them (http://img230.imageshack.us/img230/2916/rampz.jpg [img230.imageshack.us]).
Technical Discussion » Reorient vector attributes for Fur SOP
- archie
- 71 posts
- Offline
Hello, Derrick!
Thanks for the detailed answer.
My suppose that rest{x,y,z}dir values provided as an arbitrary 3x3 transformation (rotation, scales, shears) seems to be true. But it seems that in this case we have caught our own tail . The error is that there is only one way to transfer combing vectors (“furdirection”) from rest to deform pose - this is AttribReorient SOP. But it computes only rotation.
Your idea that I should pay attention on shears, has led me to the simple test:
I will create “furdirection” vectors for rest pose and then use them for growing up fur. The result is on the image http://img41.imageshack.us/img41/4464/img01k.jpg [img41.imageshack.us]. Then I will create shear deformation for skin geometry and use AttribReorient SOP for reorient “furdirection” from rest to deform pose. Look at the picture http://img297.imageshack.us/img297/3739/img02q.jpg [img297.imageshack.us]. What can one see? One can see an error serious enough. The correct result is presented on this picture http://img154.imageshack.us/img154/7946/img03e.jpg [img154.imageshack.us].
I think that if I'll use own (custom)Comb SOP, I can receive correct result if the matrix of rest{x,y,z}dir values was correctly computed. But what shall I do, if I'll use the Guide Geometry? I do not know how can one compute this matrix and therefore cannot correctly comb guide curves. May be in following release we can have expanded functionality of AttribReorient SOP or a new SOP for reorientation vector attributes which would consider both rotation,scale and shear. What do you think about it? May be there is another solution for correct fur behavior on deformed geometry?
Thanks for the detailed answer.
My suppose that rest{x,y,z}dir values provided as an arbitrary 3x3 transformation (rotation, scales, shears) seems to be true. But it seems that in this case we have caught our own tail . The error is that there is only one way to transfer combing vectors (“furdirection”) from rest to deform pose - this is AttribReorient SOP. But it computes only rotation.
Your idea that I should pay attention on shears, has led me to the simple test:
I will create “furdirection” vectors for rest pose and then use them for growing up fur. The result is on the image http://img41.imageshack.us/img41/4464/img01k.jpg [img41.imageshack.us]. Then I will create shear deformation for skin geometry and use AttribReorient SOP for reorient “furdirection” from rest to deform pose. Look at the picture http://img297.imageshack.us/img297/3739/img02q.jpg [img297.imageshack.us]. What can one see? One can see an error serious enough. The correct result is presented on this picture http://img154.imageshack.us/img154/7946/img03e.jpg [img154.imageshack.us].
I think that if I'll use own (custom)Comb SOP, I can receive correct result if the matrix of rest{x,y,z}dir values was correctly computed. But what shall I do, if I'll use the Guide Geometry? I do not know how can one compute this matrix and therefore cannot correctly comb guide curves. May be in following release we can have expanded functionality of AttribReorient SOP or a new SOP for reorientation vector attributes which would consider both rotation,scale and shear. What do you think about it? May be there is another solution for correct fur behavior on deformed geometry?
Technical Discussion » Reorient vector attributes for Fur SOP
- archie
- 71 posts
- Offline
Hello all,
What is a better way to reorient vector attributes from rest position to deform position for Fur SOP?
I know two ways to solve this problem:
1) One can use AttribReorient SOP before Fur SOP.
2) One can use restxdir, restydir, restzdir attributes which are presented as a matrix.
For reorientation of the necessary vector, you should multiply it by this matrix.
Both results are quite similar, but have a few differences.
For example:
For each point of rest geometry I create a coordinate system:
(http://img529.imageshack.us/img529/1027/img01v.jpg [img529.imageshack.us])
The yellow vector (called “furdirection”) will present vector of direction.
The green vector (called “furroll”) will present axis of roll.
And the red vector (called “furinclination”) will present axis of inclination.
For both ways, I have to use AttribReorient SOP for “furdirection” and then write value of “furdirection” in normal.
Next, for first way, I will use AttribReorient SOP for “furroll” and “furinclination”. You can see the result for deformed geometry on http://img43.imageshack.us/img43/7703/img02.jpg [img43.imageshack.us]
For second way, I will use a CVEX shader, where I will reorient “furroll” and “furinclination” for each vertex of curve of fur (http://img41.imageshack.us/img41/6600/img02b.jpg [img41.imageshack.us])
You can see both results:http://img39.imageshack.us/img39/7573/img03u.jpg [img39.imageshack.us] For the best representation I set a small density of hair.
In order to see the difference between two methods I will create two simple CVEX shaders and each will have two parameters:
The first parameter (called “inclination”) controlling angle of hair inclination to the surface.
The second parameter (called “roll”) controlling angle of hair roll around the “furroll”.
You can see both shaders on image:http://img529.imageshack.us/img529/8105/img04b.jpg [img529.imageshack.us]
Next, I merge two results and set value for inclination and roll. The result is on http://img43.imageshack.us/img43/8162/img05o.jpg [img43.imageshack.us], also I presented result with “furroll” and “furinclination” on http://img41.imageshack.us/img41/6697/img06r.jpg [img41.imageshack.us]
Both results are quite similar, but one can obviously see difference.
Which result is more accurate and why we see such a difference?
I like the result of the first way, since it has more control. For the second way, we do not know how the matrix has been computed by Fur SOP and can only guess.
What is a better way to reorient vector attributes from rest position to deform position for Fur SOP?
I know two ways to solve this problem:
1) One can use AttribReorient SOP before Fur SOP.
2) One can use restxdir, restydir, restzdir attributes which are presented as a matrix.
For reorientation of the necessary vector, you should multiply it by this matrix.
Both results are quite similar, but have a few differences.
For example:
For each point of rest geometry I create a coordinate system:
(http://img529.imageshack.us/img529/1027/img01v.jpg [img529.imageshack.us])
The yellow vector (called “furdirection”) will present vector of direction.
The green vector (called “furroll”) will present axis of roll.
And the red vector (called “furinclination”) will present axis of inclination.
For both ways, I have to use AttribReorient SOP for “furdirection” and then write value of “furdirection” in normal.
Next, for first way, I will use AttribReorient SOP for “furroll” and “furinclination”. You can see the result for deformed geometry on http://img43.imageshack.us/img43/7703/img02.jpg [img43.imageshack.us]
For second way, I will use a CVEX shader, where I will reorient “furroll” and “furinclination” for each vertex of curve of fur (http://img41.imageshack.us/img41/6600/img02b.jpg [img41.imageshack.us])
You can see both results:http://img39.imageshack.us/img39/7573/img03u.jpg [img39.imageshack.us] For the best representation I set a small density of hair.
In order to see the difference between two methods I will create two simple CVEX shaders and each will have two parameters:
The first parameter (called “inclination”) controlling angle of hair inclination to the surface.
The second parameter (called “roll”) controlling angle of hair roll around the “furroll”.
You can see both shaders on image:http://img529.imageshack.us/img529/8105/img04b.jpg [img529.imageshack.us]
Next, I merge two results and set value for inclination and roll. The result is on http://img43.imageshack.us/img43/8162/img05o.jpg [img43.imageshack.us], also I presented result with “furroll” and “furinclination” on http://img41.imageshack.us/img41/6697/img06r.jpg [img41.imageshack.us]
Both results are quite similar, but one can obviously see difference.
Which result is more accurate and why we see such a difference?
I like the result of the first way, since it has more control. For the second way, we do not know how the matrix has been computed by Fur SOP and can only guess.
Technical Discussion » How to delete an attribute in a python script?
- archie
- 71 posts
- Offline
Hi, Graham!
Thank you for answer.
My case is quite simple. I have a digital asset, that can create some results and for each result asset will create some attributes, which will be used for internal calculations. It will be nice if this attributes will be removed after calculations are finished. I know a common list of attributes to remove, but I don't know the list of attributes for every particular generated result. Thus I have to create a list of attributes to be removed for particular result with existance verification and then specify it for Attributes SOP.
I would like to make a nice and simple network. I see two ways: either I will create custom Python SOP, which will delete in loop every attribute from common list after existance verification (“destroy” method in the hou.Attrib) or I will specify common list for Attribute SOP, but this case Attribute SOP gives a warning if the specified attribute(s) does not exist. Warning is good for checking, but the network looks dirty (I don't like warnings which are not necessary ). It will be nice, if “Attribute SOP” will have “skip warning” mode: if attribute(s) does not exist the warning will not be generated.
Thank you for answer.
My case is quite simple. I have a digital asset, that can create some results and for each result asset will create some attributes, which will be used for internal calculations. It will be nice if this attributes will be removed after calculations are finished. I know a common list of attributes to remove, but I don't know the list of attributes for every particular generated result. Thus I have to create a list of attributes to be removed for particular result with existance verification and then specify it for Attributes SOP.
I would like to make a nice and simple network. I see two ways: either I will create custom Python SOP, which will delete in loop every attribute from common list after existance verification (“destroy” method in the hou.Attrib) or I will specify common list for Attribute SOP, but this case Attribute SOP gives a warning if the specified attribute(s) does not exist. Warning is good for checking, but the network looks dirty (I don't like warnings which are not necessary ). It will be nice, if “Attribute SOP” will have “skip warning” mode: if attribute(s) does not exist the warning will not be generated.
Technical Discussion » How to delete an attribute in a python script?
- archie
- 71 posts
- Offline
Hello all,
I want to delete some attributes in a python script, but “destroy” method is not implemented in the hou.Attrib.
How to delete attributes in script language, without using SOP Attribute?
I want to delete some attributes in a python script, but “destroy” method is not implemented in the hou.Attrib.
How to delete attributes in script language, without using SOP Attribute?
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