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Poser - OFFICIAL F.A.Q (Last Updated: 2025 Jan 06 7:01 am)



Subject: reflecting wrong angles


ghostship2 ( ) posted Fri, 12 April 2013 at 10:12 PM · edited Fri, 12 July 2024 at 10:59 AM

file_493537.jpg

Im getting reflection of his skin/head on the front of the coif. it moves with camera angle.  goes away when I turn off bump and displacement. anybody know what's going on with this?

PP2010, IDL on, using BB evirosphere, no lights are on 

any help with this would be great

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


hborre ( ) posted Fri, 12 April 2013 at 10:41 PM · edited Fri, 12 April 2013 at 10:42 PM
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What is the gamma setting on your bump/displacement map?  In the Texture Manager it should be 1.


bagginsbill ( ) posted Fri, 12 April 2013 at 10:43 PM · edited Fri, 12 April 2013 at 10:45 PM

What do you have your Poser Display Unit set to? I need to know that in order to interpret the ray bias in the reflect node.

Once we know your PDU, I will likely point out that your ray bias is .762 PDU - e.g. .762 inch or .762 meters. Then we will examine what that means. In any case, it's probably too high.

It is important to know what ray bias is for - it's to cause a reflection from a surface to ignore that same surface for a while. This doesn't sound logical and it's actually because of an undesirable artifact. It's a hack.

In your case, I am suspicious that you have curved the surface with your bump/displacement, and that the reflections of certain angles lead to the skin, but would logically not reach it and are only doing so because the ray bias causes the coif to ignore itself.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


ghostship2 ( ) posted Sat, 13 April 2013 at 12:12 AM

hborre,

gamma set to 2.2, .45 (inverse of 2.2 I think) for grey maps. I always use this and it seems to work out better than 1 for hair/lash maps but I could be totaly wrong and my math could be wrong as well.

bagginsbill,

From what I read in the poser ref man about the refl node I had figured it was ray bias based on what it does but it's one of those controls that I don't mess with and leave on default.

poser dispaly units is set to centimeter.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


Eric Walters ( ) posted Sat, 13 April 2013 at 2:54 AM

I always forget ray bias! Thanks for bringing this up.

I am also in the Bay Area. Nice weather lately!

quote]

hborre,

gamma set to 2.2, .45 (inverse of 2.2 I think) for grey maps. I always use this and it seems to work out better than 1 for hair/lash maps but I could be totaly wrong and my math could be wrong as well.

bagginsbill,

From what I read in the poser ref man about the refl node I had figured it was ray bias based on what it does but it's one of those controls that I don't mess with and leave on default.

poser dispaly units is set to centimeter.



ghostship2 ( ) posted Sat, 13 April 2013 at 10:07 PM

I messed with ray bias for an hour. All I could get it to do was shift around the bad skin reflections. I gave up and changed my bump and displacement settings and a few other things in the mat.

I know nothing about ray bias except what it's supposed to do and am the last person that should be messing with it ;)

yeah the weather here has been nice...got cold tonight.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


bagginsbill ( ) posted Sat, 13 April 2013 at 10:16 PM · edited Sat, 13 April 2013 at 10:19 PM

I notice your bump depth is .9 cm, right? That's enormous. You're creating a virtual surface that has hills and valleys that are way bigger than you realize.

Disconnect the bump, and use displacement - put .9 in the displacement and observe what you're doing to the surface.

Bump doesn't move the surface like displacement, but it still calculates the angles as if it had moved.

It's hard to tell exactly what is in your bump map, but if it's all bright like that, you're pushing the whole thing out. In poser, 0 = black and that is the only value that doesn't move the surface.

You should be using an offset, subtracting the neutral value of your map from the map itself, so that your neutral value causes no movement.

For example, if gray 180 is supposed to be "no change", then you should be running the map into a color_math node and subtract gray 180 in Value_2.

If you have gamma on, this gets a bit more complicated.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


ghostship2 ( ) posted Sun, 14 April 2013 at 11:37 AM

in my experiments I had plugged in an HSV node and turned down the value a little. I also made a few variations of the map with different amounts of contrast.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


bagginsbill ( ) posted Sun, 14 April 2013 at 2:07 PM

But did you do what I said? Show it as real displacement and look at the surface you created with a .9 cm displacement.

It's going to look like a hair brush.


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


ghostship2 ( ) posted Sun, 14 April 2013 at 4:53 PM

file_493568.jpg

yeah, I had played with all manner of bump/displacement settings and it did not matter if it was bump or displacement that was being set high, both gave the same strange reflections. I settled on lowering bump/displacement and messing with reflect amount and a contrasty map controling it.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


ghostship2 ( ) posted Sun, 14 April 2013 at 4:59 PM

forgot to say that I also set my PDU back to PDU from centimeter. I think I had changed that setting a few weeks ago.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


Miss Nancy ( ) posted Sun, 14 April 2013 at 7:49 PM

ghost, that last one is better IMVHO,  but you need to use bill's basic fresnel reflection shader or snarly's ezmetal, as refl value = 3 violates fresnel's law.  if said coif is freebie, post link that one of us might render it.

is that frisco bay area?  been bloody windy lately.



ghostship2 ( ) posted Sun, 14 April 2013 at 8:34 PM

Miss Nancy

Im using PP2010 so if any of that needs sss or any of the new nodes that only come with 2012 im out of luck. Im waiting for the new version of Poser to come out.

Ill take another look at the shader but heck if it is working now why mess with it.

Im a cheat...The coif is Adamthwaits ninja hood from his huge M3 spy pack in RMP. I could not find a coif anywhere and also had to make my own jousting lance because I couldnt find any of those either.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


bagginsbill ( ) posted Mon, 15 April 2013 at 8:00 AM · edited Mon, 15 April 2013 at 8:07 AM

It's not 3 because he plugged in the HSV, which is .25.

You did a bunch of work to come up with .75 there.

Map * .25 * 3 = Map * .75

Maybe I need to write an article about multiplication. I've described this dozens of times, but even the old-timers don't remember it.

When you plug something in to one of those _color and _value pairs, the color in the _color chip is multiplied with the thing you plug in, the number in the _value is multiplied with whatever you plug in, and the whole thing is multiplied together.

In the HSV node, the color chip is multiplied with what you plug in and then multiplied with the value in the value parameter (and whatever is plugged in as well) - meaning that HSV is partially identical to a _color _value pair of inputs like on the root surface node.

Every time you use white in a parameter chip, you're multiplying with 1.

You could put 30 of these together and you'd still end up with nothing more than a single numeric factor. Example:

You hook a map to HSV with the HSV color set to WHITE, value=70.

You plug that into another HSV with color WHITE, value = .1. You're now at 7.

You plug that into Reflection_Color and set Reflection_Value = .12 - you're now at .84

Furthermore:

The order you multiply does not alter the product - multiplication is commutative.

a * b = b * a

So - in my hypothetical example, you could set the Reflection_Value = 70, and the first HSV to .12, and it would still come out as .84

70 * .1 * .12 = .84 = .12 * .1 * 70


Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)


ghostship2 ( ) posted Tue, 16 April 2013 at 10:22 AM

file_493646.jpg

BB

I turned down the reflect to 1 and removed the HSV node. 

It doesnt seem that all values follow the same rule in poser mats. In the reflect node for instance, the softness control make the reflection softer till you get to a value of 4, any more than that and it starts to look ugly. other controls go on the 1=100% rule and interact with other things as you have mentioned in other posts. 

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


ghostship2 ( ) posted Tue, 16 April 2013 at 10:25 AM

Id also like to note that in these last two renders I corrected levels in photoshop. I have to do this with pretty much all my renders.

W10, Ryzen 5 1600x, 16Gb,RTX2060Super+GTX980, PP11, 11.3.740


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