User:Wfpokorny/DensityFile - Revision history

Wfpokorny: Updates to better reflect current POV-Ray versions and not presume patch adoption version.

2018-01-04T18:38:57Z

Updates to better reflect current POV-Ray versions and not presume patch adoption version.

Wfpokorny: Playpen status updates.

2017-01-19T13:36:09Z

Playpen status updates.

Wfpokorny: Corrected header given recent edits.

2016-09-12T08:44:47Z

Corrected header given recent edits.

Wfpokorny: Removing mention of possible further enhancements for cleaner documentation.

2016-08-31T11:51:37Z

Removing mention of possible further enhancements for cleaner documentation.

Wfpokorny: Restoring df3-bowl-lathe example.

2016-08-29T14:30:30Z

Restoring df3-bowl-lathe example.

Wfpokorny: Update for backward compatibility modes and mention of work on UberPov patch version.

2016-08-28T13:44:26Z

Update for backward compatibility modes and mention of work on UberPov patch version.

Wfpokorny: Removing a couple main file examples. Perhaps later restore as an additional full example.

2016-08-20T14:12:55Z

Removing a couple main file examples. Perhaps later restore as an additional full example.

Wfpokorny: Initial edit removing helper interpolations 6 through 12. Example updates will come later.

2016-08-20T14:00:38Z

Initial edit removing helper interpolations 6 through 12. Example updates will come later.

Wfpokorny: Typo

2016-08-18T17:31:01Z

Typo

Wfpokorny: Added a sub-header.

2016-08-18T17:23:37Z

Added a sub-header.

@@ Line 10: / Line 10: @@
 {{#indexentry:df3}}
-<p>'''Note!''' While the following density_file (.df3) pattern documentation is often valid with respect to the current 3.7.0 forms of df3 value interpolation, it is written as if the additional interpolation modes proposed in  https://github.com/wfpokorny/povray/tree/feature/newDensityPatternInterpolations have been adopted.</p>
+<p>'''Note!''' While the following density_file (.df3) pattern documentation is often valid with respect to the current 3.7 and 3.8 forms of df3 value interpolation, it is written as if the additional interpolation modes proposed in https://github.com/wfpokorny/povray/tree/feature/newDensityPatternInterpolations have been adopted.</p>
-<p>'''Note!''' After some discussion it's been decided the 'assist' interpolation modes 6-12 will be dropped for methods already supported. Wiki edits are mostly complete to match and the source code has been updated.</p>
+<p>'''Note!''' After some discussion it's was decided the original 'assist' interpolation modes 6-12 would be dropped for methods already supported. However, newer texturing assist modes 9 & 10 are currently in play in the patch and not well documented.</p>
 = Density File Pattern =
@@ Line 63: / Line 63: @@
 === Interpolation options. ===
-<p>There are currently 6 data interpolation types numbered 0 through 5, with the types larger than 2 being available only in releases 3.7.1 and later. If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel is returned. The other interpolation methods available are:</p>
+<p>There are currently 6 data interpolation types numbered 0 through 5, with the types larger than 2 being available only with the patch. If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel is returned. The other interpolation methods available are:</p>
 <ol>
@@ Line 71: / Line 71: @@
 <li> Moderate  exponential blobbing of defined voxels in 6x6x6 local sub regions.
 <li> Strong exponential blobbing of defined voxels in 8x8x8 local sub regions.
 </ol>
@@ Line 88: / Line 93: @@
 <p>The algorithm has been tuned so 1.0 values for each of the exponential blobbing interpolations just fit within the corresponding sub cube. The blobbing can be adjusted without the need to regenerate a df3 by using the standard pattern wave modifier poly_wave <float>. Poly_wave values >=1.0 should always work and reduce the blobbing. Values < 1.0 increase the blobbing and can cause sub cube overruns. Overruns will appear as discontinuities in the final pattern.</p>
-=== Only interpolation 0 is voxel centered in 3.7.0 and earlier releases. ===
+=== Only interpolation 0 is voxel centered in 3.8.0 and earlier releases. ===
-<p>For version 3.7.0, the interpolations 0 to 2 are shown below in order, left to right, as a pigment on a plane for an 11x11x11 df3 file where a single center voxel has a value of 0.5 while all others are 0.0. The red dots mark the vertices around our center voxel.</p>
+<p>For version 3.7.0 and 3.8, the interpolations 0 to 2 are shown below in order, left to right, as a pigment on a plane for an 11x11x11 df3 file where a single center voxel has a value of 0.5 while all others are 0.0. The red dots mark the vertices around our center voxel.</p>
 [[Image:Df3_I0thru2_370.png|center|frame|Density_file interpolations for single center voxel as a green pigment on a plane with release 3.7.0.]]
-<p>The tri-linear and tri-cubic interpolations are vertex centered prior to 3.7.1 resulting in a half voxel negative shift in x,y,z .  This shift is perhaps of no consequence if rendering media. It does however matter if, for example, building a df3 based isosurface or when trying to control textures for media for any formed objects using interpolation 0.</p>
+<p>The tri-linear and tri-cubic interpolations are vertex centered without the patch resulting in a half voxel negative shift in x,y,z .  This shift is perhaps of no consequence if rendering media. It does however matter if, for example, building a df3 based isosurface or when trying to control textures for media for any formed objects using interpolation 0.</p>
 <p>Offset tri-linear and tri-cubic results can be centered with a positive translation of one half a voxel size in x,y and z. For the 11x11x11 df3 example use:</p>
@@ Line 103: / Line 108: @@
 <pre>FnctAdjustToCenter(x+0.5-(1/11/2),y+0.5-(1/11/2),z+0.5-(1/11/2))</pre>
-=== Release 3.7.1 makes all interpolations voxel, and so too unit cube, centered. ===
+=== The patch makes all interpolations voxel, and so too unit cube, centered. ===
-<p>In addition to adding density_file pattern interpolation modes, 3.7.1 centers all the interpolated results. The 3.7.1 interpolations 0 to 5 are shown in order, left to right, in the following image.</p>
+<p>In addition to adding density_file pattern interpolation modes, the patch centers all the interpolated results. The patch interpolations 0 to 5 are shown in order, left to right, in the following image.</p>
 [[Image:Df3_I0thru5_371.png|center|frame|Density_file interpolations for single center voxel as a green pigment on a plane.]]
@@ Line 129: / Line 134: @@
 === Use a buffer of five 0.0 voxels on all sides to avoid density_file edge effects. ===
-<p>While not a hard and fast rule, all the interpolations other than 0, and 6-12, will wrap or repeat values on the sides. The general recommendation of five comes from interpolation five's need for an 8 grid range (4 per side) about any evaluated point - plus a half voxel grid for the internal vertex to voxel center correction of interpolations 1-5. Often smaller buffer amounts can be used.</p>
+<p>While not a hard and fast rule, all the interpolations other than 0, 9 and 10, will wrap or repeat values on the sides. The general recommendation of five comes from interpolation five's need for an 8 grid range (4 per side) about any evaluated point - plus a half voxel grid for the internal vertex to voxel center correction of interpolations 1-5. Often smaller buffer amounts can be used.</p>
 <p>Below are two images. In the first, the lower-left-forward corner of the df3 has been filled with 0.2 values with all others 0.0. In the second image the top-right-back corner of df3 file has been set to values of 0.2 with all others set to 0.0. Interpolations 0 through 5 are shown left to right in each of these two images as a pigment on an x,y plane at the df3 unit cube's z center.</p>
@@ Line 164: / Line 169: @@
 </pre>
-<p>The include file arrays.inc is already part of POV-Ray and the arraycoupleddf3s.inc file is given in the examples section. Once the df3 representation of the 2D image exists, the following code is used to create the function for the isosurface text using blobbing interpolation 5.</p>
+<p>The include file arrays.inc is already part of POV-Ray and the arraycoupleddf3s.inc file is given in the examples section and is part of the Github patch branch. Once the df3 representation of the 2D image exists, the following code is used to create the function for the isosurface text using blobbing interpolation 5.</p>
 <pre>

@@ Line 10: / Line 10: @@
 {{#indexentry:df3}}
-<p>'''Note!''' While the following density_file (.df3) pattern documentation is often valid with respect to the current 3.7.0 forms of df3 value interpolation, it is written as if the additional interpolation modes proposed in  https://github.com/wfpokorny/povray/tree/feature/newDensityPatternInterpolations have been adopted for the 3.7.1 release. An UberPOV patch version is in the works.</p>
+<p>'''Note!''' While the following density_file (.df3) pattern documentation is often valid with respect to the current 3.7.0 forms of df3 value interpolation, it is written as if the additional interpolation modes proposed in  https://github.com/wfpokorny/povray/tree/feature/newDensityPatternInterpolations have been adopted.</p>
 <p>'''Note!''' After some discussion it's been decided the 'assist' interpolation modes 6-12 will be dropped for methods already supported. Wiki edits are mostly complete to match and the source code has been updated.</p>

@@ Line 143: / Line 143: @@
 <p>The exponential blobbing of 3 through 5 all repeat - or add values - at the last voxel position at the sides. This can sometimes be compensated for by lowering the on side and in-corner values.</p>
-=== df3 file size, 2D extrusion, twist and lathe methods. ===
+=== df3 file size. ===
 <p>Df3 files can get very large, very quickly given the cubed dimensions. A df3 1000x1000x1000 at 1 byte resolution will take a gigabyte of storage. It practice, aim to reduce the z dimension as much as possible letting the density_file pattern scale up to the unit cube. Later scale the unit cube dimension to the desired final size.</p>

← Older revision		Revision as of 11:51, 31 August 2016
Line 87:		Line 87:

	<p>The algorithm has been tuned so 1.0 values for each of the exponential blobbing interpolations just fit within the corresponding sub cube. The blobbing can be adjusted without the need to regenerate a df3 by using the standard pattern wave modifier poly_wave <float>. Poly_wave values >=1.0 should always work and reduce the blobbing. Values < 1.0 increase the blobbing and can cause sub cube overruns. Overruns will appear as discontinuities in the final pattern.</p>		<p>The algorithm has been tuned so 1.0 values for each of the exponential blobbing interpolations just fit within the corresponding sub cube. The blobbing can be adjusted without the need to regenerate a df3 by using the standard pattern wave modifier poly_wave <float>. Poly_wave values >=1.0 should always work and reduce the blobbing. Values < 1.0 increase the blobbing and can cause sub cube overruns. Overruns will appear as discontinuities in the final pattern.</p>
−
−	<p>A note on a possible extension to the density_file exponential blobbing methods. These today are based upon the square of the distance to nearby voxels with a value >0.0 and a strength blobbing factor based upon the value of those >0.0 voxels. When blobbing, the deeper 2 byte and 4 byte df3 formats are not often used. It is possible, with the 2 byte and 4 byte depths, to use 1 byte for the blobbing strength factor, and the remaining byte(s) to offset the evaluated voxel center for the distance squared component. At the 32 bit depth there would be 8x8x8 or 512 possible sub-voxel positions. Unsure of the ultimate performance for such code, the modeling/creating of df3s is certainly less straight forward, and such a method would be restricted to sparse data representations. Up to a 3x3x3, same weight (1/32 accuracy), bit representation at the 32 bit depth would be available too, if density of voxels were the aim.</p>

	=== Only interpolation 0 is voxel centered in 3.7.0 and earlier releases. ===		=== Only interpolation 0 is voxel centered in 3.7.0 and earlier releases. ===

← Older revision		Revision as of 14:30, 29 August 2016
Line 224:		Line 224:

	[[User:Wfpokorny/DensityFile/FillingVolumeWithShapes\|Filling a volume with many individually textured shapes.]]		[[User:Wfpokorny/DensityFile/FillingVolumeWithShapes\|Filling a volume with many individually textured shapes.]]
		+
		+	[[User:Wfpokorny/DensityFile/Bowl\|Isosurace lathe where base df3 created from array of strings.]]

	[[User:Wfpokorny/DensityFile/Twist\|Place holder for twist example. Perhaps not worth keeping without interpolations 9,11-12?]]		[[User:Wfpokorny/DensityFile/Twist\|Place holder for twist example. Perhaps not worth keeping without interpolations 9,11-12?]]
−
−	~~[[User:Wfpokorny/DensityFile/Bowl\|Place holder for lathe example. Likely not worth keeping without interpolation 10, but perhaps for macro example]]~~

@@ Line 145: / Line 145: @@
 === df3 file size, 2D extrusion, twist and lathe methods. ===
 <p>Df3 files can get very large, very quickly given the cubed dimensions. A df3 1000x1000x1000 at 1 byte resolution will take a gigabyte of storage. It practice, aim to reduce the z dimension as much as possible letting the density_file pattern scale up to the unit cube. Later scale the unit cube dimension to the desired final size.</p>
 ==== 3D isosurface extrusion of image via shallow in z, density_file pattern. ====
-<p>A second example compressing the df3 in one dimension comes naturally when the density_file pattern is used for extrusion of a 2D image into 3D shape. The outline for such an extrusion is shown in the following code snippets with a resulting image.  A 500x500x13 deep df3 of the red in a 2D image, at left below, is created with the following code:</p>
+<p>An example compressing the df3 in one dimension comes naturally when the density_file pattern is used for extrusion of a 2D image into 3D shape. The outline for such an extrusion is shown in the following code snippets with a resulting image.  A 500x500x13 deep df3 of the red in a 2D image, at left below, is created with the following code:</p>
 <pre>
@@ Line 226: / Line 184: @@
 <p>Function Fnct01 gets used in the isosurface  and the general form here works more or less universally with the density_file pattern when the isosurface threshold is 0.0. '''Note.''' While a couple of functions are required for the isosurface set up, the standard pattern modifiers do most of the work.</p>
 === Performance of various interpolations. ===
@@ Line 350: / Line 222: @@
 [[User:Wfpokorny/DensityFile/FillingVolumeWithShapes|Filling a volume with many individually textured shapes.]]

@@ Line 11: / Line 11: @@
 <p>'''Note!''' While the following density_file (.df3) pattern documentation is often valid with respect to the current 3.7.0 forms of df3 value interpolation, it is written as if the additional interpolation modes proposed in  https://github.com/wfpokorny/povray/tree/feature/newDensityPatternInterpolations have been adopted for the 3.7.1 release.</p>
 = Density File Pattern =
@@ Line 18: / Line 20: @@
 <pre>density_file df3 [file name] [interpolate Type]</pre>
-where the file name would be placed in double quotes and the interpolation type would be an integer value 0 through 12. For example:
+where the file name would be placed in double quotes and the interpolation type would be an integer value 0 through 5. For example:
 <pre>density_file df3 "star.df3" 1</pre>
@@ Line 61: / Line 63: @@
 === Interpolation options. ===
-<p>There are currently thirteen data interpolation types numbered 0 through 12, with the types larger than 2 being available only in releases 3.7.1 and later.  If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel  is returned. The other interpolation methods available are:</p>
+<p>There are currently 6 data interpolation types numbered 0 through 5, with the types larger than 2 being available only in releases 3.7.1 and later. If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel is returned. The other interpolation methods available are:</p>
 <ol>
@@ Line 69: / Line 71: @@
 <li> Moderate  exponential blobbing of defined voxels in 6x6x6 local sub regions.
 <li> Strong exponential blobbing of defined voxels in 8x8x8 local sub regions.
 </ol>
@@ Line 94: / Line 89: @@
 <p>A note on a possible extension to the density_file exponential blobbing methods. These today are based upon the square of the distance to nearby voxels with a value >0.0 and a strength blobbing factor based upon the value of those >0.0 voxels. When blobbing, the deeper 2 byte and 4 byte df3 formats are not often used. It is possible, with the 2 byte and 4 byte depths, to use 1 byte for the blobbing strength factor, and the remaining byte(s) to offset the evaluated voxel center for the distance squared component. At the 32 bit depth there would be 8x8x8 or 512 possible sub-voxel positions. Unsure of the ultimate performance for such code, the modeling/creating of df3s is certainly less straight forward, and such a method would be restricted to sparse data representations. Up to a 3x3x3, same weight (1/32 accuracy), bit representation at the 32 bit depth would be available too,  if density of voxels  were the aim.</p>
 === Only interpolation 0 is voxel centered in 3.7.0 and earlier releases. ===
@@ Line 154: / Line 142: @@
 <p>The exponential blobbing of 3 through 5 all repeat - or add values - at the last voxel position at the sides. This can sometimes be compensated for by lowering the on side and in-corner values.</p>
 === df3 file size, 2D extrusion, twist and lathe methods. ===
@@ Line 385: / Line 314: @@
 === Performance of various interpolations. ===
-<p>Generally the internal pattern performance  in terms of the interpolation numbers runs (7-9)-->0 â (6,10-12) --> 1 --> 3 --> 2 --> 4 --> 5 from fastest to slowest with a strong dependence on df3 data density, values and ultimate pattern use. As pigments all perform well. Media and isosurface use will amplify the performance differences. With respect to isosurfaces and remembering how the gradients change, it happens for larger df3 values, interpolation 5 can be the fastest of 1-5 because the isosurface gradients are in that case the most gradual.</p>
+<p>Generally the internal pattern performance  in terms of the interpolation numbers runs 0 --> 1 --> 3 --> 2 --> 4 --> 5 from fastest to slowest with a strong dependence on df3 data density, values and ultimate pattern use. As pigments all perform well. Media and isosurface use will amplify the performance differences. With respect to isosurfaces and remembering how the gradients change, it happens for larger df3 values, interpolation 5 can be the fastest because the isosurface gradients are in that case the most gradual.</p>
 === Tip. Using frequency 0 for better performance. ===

← Older revision		Revision as of 17:31, 18 August 2016
Line 127:		Line 127:
	<p>The former better showing the crease effect of tri-linear interpolation, the latter, the ring of tri-cubic interpolation. The tri-cubic mode always wobbles, but the most severe artifacts can be avoided by using values not near 0.0 and 1.0 where pattern clipping occurs.</p>		<p>The former better showing the crease effect of tri-linear interpolation, the latter, the ring of tri-cubic interpolation. The tri-cubic mode always wobbles, but the most severe artifacts can be avoided by using values not near 0.0 and 1.0 where pattern clipping occurs.</p>

−	~~{{./isoBoxOnSpindle.png}}~~
	[[Image:Df3_isoBoxOnSpindle.png\|center\|frame\|Density_file interpolations 1-5 for defined voxels arranged as box on spindle.]]		[[Image:Df3_isoBoxOnSpindle.png\|center\|frame\|Density_file interpolations 1-5 for defined voxels arranged as box on spindle.]]

← Older revision		Revision as of 17:23, 18 August 2016
Line 60:		Line 60:
	<p>The density pattern occupies the unit cube <0,0,0> to <1,1,1> regardless of the x, y, z dimensions in voxels. It remains at 0.0 for all areas beyond the unit cube. Data values in the ranges of 0 to 255 (8 bit/1 byte), 0 to 65535 (16 bit/2 bytes) and 0 to 4294967295 (32 bit/4 bytes), are scaled by the various interpolation methods to a float value in the range 0.0 to 1.0. The larger 2 byte and 4 byte depths providing better resolution.</p>		<p>The density pattern occupies the unit cube <0,0,0> to <1,1,1> regardless of the x, y, z dimensions in voxels. It remains at 0.0 for all areas beyond the unit cube. Data values in the ranges of 0 to 255 (8 bit/1 byte), 0 to 65535 (16 bit/2 bytes) and 0 to 4294967295 (32 bit/4 bytes), are scaled by the various interpolation methods to a float value in the range 0.0 to 1.0. The larger 2 byte and 4 byte depths providing better resolution.</p>

		+	=== Interpolation options. ===
	<p>There are currently thirteen data interpolation types numbered 0 through 12, with the types larger than 2 being available only in releases 3.7.1 and later. If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel is returned. The other interpolation methods available are:</p>		<p>There are currently thirteen data interpolation types numbered 0 through 12, with the types larger than 2 being available only in releases 3.7.1 and later. If nothing is specified via the interpolate keyword, the default is 0 which does no interpolation - meaning for a given location in the unit cube, the 0.0 to 1.0 value of the containing voxel is returned. The other interpolation methods available are:</p>