Documentation Talk:Reference Section 6.2 - Revision history

Jholsenback: another stab at it ...

2010-04-14T11:37:49Z

another stab at it ...

Jholsenback: follow up

2010-04-14T09:38:49Z

follow up

Clipka at 19:55, 13 April 2010

2010-04-13T19:55:46Z

Clipka: /* pass_through */ new section

2010-04-13T19:52:32Z

pass_through: new section

Clipka: deleted my previous edit; it was wrong (unfortunately)

2010-04-13T11:53:29Z

deleted my previous edit; it was wrong (unfortunately)

Clipka: pass_through

2010-04-13T11:43:09Z

pass_through

New page

<p>The keyword <code>pass_through</code> causes photons to pass through the
object <strong>unaffected</strong> on their way to a target object. Once a
photon hits the target object, it will ignore the <code>pass_through</code>
flag. This is basically a photon version of the <code>no_shadow</code>
keyword. If you use the <code>no_shadow</code> keyword, the object will be tagged as
<code>pass_through</code> automatically. You can then turn off
<code>pass_through</code> if necessary by simply using <code>photons {
pass_through off }</code>.</p>

[clipka - Removed the mentioning of media still collecting photons, as it was wrong (fortunately) even for 3.6: on their way to their target, photons are ''never'' collected by other objects, whether they are pass_through or otherwise.]

← Older revision		Revision as of 11:37, 14 April 2010
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	<code>pass_through</code> if necessary by simply using <code>photons {		<code>pass_through</code> if necessary by simply using <code>photons {
	pass_through off }</code>.</p> --[[User:Jholsenback\|jholsenback]] 09:38, 14 April 2010 (UTC)		pass_through off }</code>.</p> --[[User:Jholsenback\|jholsenback]] 09:38, 14 April 2010 (UTC)
		+
		+
		+	* ok ... after reading this about a bazillion times this is what I've come up with ... sheesh
		+
		+
		+	<p>The keyword <code>pass_through</code> causes photons to pass through the object <strong>unaffected</strong> on their way to a target object. Once a photon hits the target object, it will ignore the <code>pass_through</code> flag. This is basically a photon version of the <code>no_shadow</code> keyword, and photons on their way to their target are <em>never</em> collected by any surface or media whatsoever. If you use the <code>no_shadow</code> keyword, the object will be tagged as
		+	<code>pass_through</code> automatically, and will suppress <em>any</em> interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.
		+	</p>
		+
		+	:* --[[User:Jholsenback\|jholsenback]] 11:37, 14 April 2010 (UTC)

@@ Line 14: / Line 14: @@
 Marking an object as <code>no_shadow</code> will also prevent it from blocking photons; however, this will not only suppress interaction with photons on their way to their target, but also with photons that have already transmitted through or reflected off their target.
 <p class="Note"><strong>Note:</strong> The documentation of POV-Ray 3.6 contained some errors regarding both <code>pass_through</code> and <code>no_shadow</code> with regard to photons:
 * Media in objects marked <code>pass_through</code> were said to still collect photons on their way to their target; ''this is not the case''. Instead, photons on their way to their target are ''never'' collected by any surface or media whatsoever.
-* It was said that specifying <code>no_shadow</code> would automatically turn on <code>pass_through</code>, and that explicitly specifying <code>pass_through off</code> could be used to disable it again; ''this is not the case''. Instead, specifying <code>no_shadow</code> will suppress ''any'' interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.</p>
+* It was said that specifying <code>no_shadow</code> would automatically turn on <code>pass_through</code>, and that explicitly specifying <code>pass_through off</code> could be used to disable it again; ''this is not the case''. Instead, specifying <code>no_shadow</code> will suppress ''any'' interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.

@@ Line 5: / Line 5: @@
 By default, any objects between the photon source and target will ''completely'' block photons, ''even if the object in question is transparent''. To explicitly allow photons to transmit through such an object, mark the object as <code>photons { pass_through }</code>.
-In POV-Ray 3.6, specifying <code>pass_through</code> this had the following effect:
+In POV-Ray 3.6, specifying <code>pass_through</code> had the following effect:
 * If the object was normally opaque, it would ''not'' block photons on their way to their target at all, and not even affect their colour.
-* If the object was partially or fully transparent, it would erroneously ''amplify'' photons on their way to their target; if the object had an IOR, part of the amplified light would even be refracted.
+* If the object was partially or fully transparent, it would erroneously ''amplify'' photons on their way to their target; if the object had an IOR, part of the amplified light would even be subject to refraction in the <code>pass_through</code> object.
-NOTE: <code>pass_through</code> only affects the interaction with photons on their way to their target; photons that have already transmitted through or reflected off their target will ''always'' interact with subsequent objects normally, regardless of the <code>pass_through</code> setting.
+<p class="Note"><strong>Note:</strong> <code>pass_through</code> only affects the interaction with photons on their way to their target; photons that have already transmitted through or reflected off their target will ''always'' interact with subsequent objects normally, regardless of the <code>pass_through</code> setting.</p>
 Marking an object as <code>no_shadow</code> will also prevent it from blocking photons; however, this will not only suppress interaction with photons on their way to their target, but also with photons that have already transmitted through or reflected off their target.
-NOTE: The documentation of POV-Ray 3.6 contained some errors regarding both <code>pass_through</code> and <code>no_shadow</code> with regard to photons:
+<p class="Note"><strong>Note:</strong> The documentation of POV-Ray 3.6 contained some errors regarding both <code>pass_through</code> and <code>no_shadow</code> with regard to photons:
 * Media in objects marked <code>pass_through</code> were said to still collect photons on their way to their target; ''this is not the case''. Instead, photons on their way to their target are ''never'' collected by any surface or media whatsoever.
-* It was said that specifying <code>no_shadow</code> would automatically turn on <code>pass_through</code>, and that explicitly specifying <code>pass_through off</code> could be used to disable it again; ''this is not the case''. Instead, specifying <code>no_shadow</code> will suppress ''any'' interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.
+* It was said that specifying <code>no_shadow</code> would automatically turn on <code>pass_through</code>, and that explicitly specifying <code>pass_through off</code> could be used to disable it again; ''this is not the case''. Instead, specifying <code>no_shadow</code> will suppress ''any'' interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.</p>

← Older revision	Revision as of 19:52, 13 April 2010
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	+	== pass_through ==

	+	Here's how it ''really currently'' works in POV-Ray 3.6:
	+
	+	By default, any objects between the photon source and target will ''completely'' block photons, ''even if the object in question is transparent''. To explicitly allow photons to transmit through such an object, mark the object as <code>photons { pass_through }</code>.
	+
	+	In POV-Ray 3.6, specifying <code>pass_through</code> this had the following effect:
	+
	+	* If the object was normally opaque, it would ''not'' block photons on their way to their target at all, and not even affect their colour.
	+	* If the object was partially or fully transparent, it would erroneously ''amplify'' photons on their way to their target; if the object had an IOR, part of the amplified light would even be refracted.
	+
	+	NOTE: <code>pass_through</code> only affects the interaction with photons on their way to their target; photons that have already transmitted through or reflected off their target will ''always'' interact with subsequent objects normally, regardless of the <code>pass_through</code> setting.
	+
	+	Marking an object as <code>no_shadow</code> will also prevent it from blocking photons; however, this will not only suppress interaction with photons on their way to their target, but also with photons that have already transmitted through or reflected off their target.
	+
	+	NOTE: The documentation of POV-Ray 3.6 contained some errors regarding both <code>pass_through</code> and <code>no_shadow</code> with regard to photons:
	+	* Media in objects marked <code>pass_through</code> were said to still collect photons on their way to their target; ''this is not the case''. Instead, photons on their way to their target are ''never'' collected by any surface or media whatsoever.
	+	* It was said that specifying <code>no_shadow</code> would automatically turn on <code>pass_through</code>, and that explicitly specifying <code>pass_through off</code> could be used to disable it again; ''this is not the case''. Instead, specifying <code>no_shadow</code> will suppress ''any'' interaction with photons whatsoever, regardless of any settings in the <code>photons</code> block.

← Older revision		Revision as of 11:53, 13 April 2010
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−	~~<!--<indexentry primary "pass_through">--->~~
−	~~<p>The keyword <code>pass_through</code> causes photons to pass through the~~
−	~~object <strong>unaffected</strong> on their way to a target object. Once a~~
−	~~photon hits the target object, it will ignore the <code>pass_through</code>~~
−	~~flag. This is basically a photon version of the <code>no_shadow</code>~~
−	~~keyword. If you use the <code>no_shadow</code> keyword, the object will be tagged as~~
−	~~<code>pass_through</code> automatically. You can then turn off~~
−	~~<code>pass_through</code> if necessary by simply using <code>photons {~~
−	~~pass_through off }</code>.</p>~~

−	[clipka - Removed the mentioning of media still collecting photons, as it was wrong (fortunately) even for 3.6: on their way to their target, photons are ''never'' collected by other objects, whether they are pass_through or otherwise.]