Simple PBR v5

It’s been awhile since I posted a new version of Simple PBR. It’s gone through a couple internal updates (one of which I brought back to v4 because I found it useful). If you want to some techno-rambling about what exactly is changed, I’ll describe it at the end of the post. A lot of you probably just want the shader and some basic instructions, so, here you go:

overview

Download it here: https://drive.google.com/open?id=0B4md98mV7RHJaGFKcVpmVjRvZ0U

There are two main nodes inside, “Simple PBR v5” and “Simple fastPBR v5”. Both give mostly similar results and have the same inputs. fastPBR is slightly faster to render. Not by much, you might not even notice the difference on big scenes, but Simple fastPBR skips a few things to optimize the shader a bit. In exchange for making you wait slightly longer, the regular version will give slightly more realistic results with higher roughness.

IMPORTANT: SIMPLE PBR v5 REQUIRES BLENDER 2.78+!!!! It is NOT compatible with 2.77a!


“Wait!! There used to be a Substance and Substance Painter shader, what do I do now?!”

Simple PBR v5 has transcended such things. You can now just use the regular Simple PBR or Simple fastPBR with Substance. An updated Blender Cycles export preset for Substance Painter is included. If you were using the one that came with Simple PBR v4, you should replace it with the new one. It will export maps for each of the 4 channels. Roughness, metallic, and normalOpenGL should be loaded as “non-color data”, base color should be loaded as the default “color”. You will need to add a normal map node in-between the normal input on the shader and your normalOpenGL image node. See below for the example setup.

Note that now all Simple PBR shaders use squared roughness. This is different from the raw glossy BSDF, but it’s easier to work with and it seems the way all the other community PBR shaders are going.


“How do I use Simple PBR?”

Glad you asked. Append it to your scene and plug it into the material output. Typically your textures go something like this:

example

The only other thing worth noting is that if you are not using a bump or normal map, you will need to manually supply the mesh normal with the geometry node as in the screenshot above (it’s set up in the source file too for your reference). This is due to some limitations with Cycles and node groups not initializing the shader normal properly in some cases, using the geometry > normal output just sets it manually to the correct value.


Simple glazePBR and Simple PBR Glass

Simple glazePBR is just the dielectric reflection component of Simple PBR. You can use it to add a realistic gloss to non-conductive objects that are not diffuse. Like, say, skin. Or you can make some sweet (and easy!) carpaint but sticking it after the regular Simple PBR.

Simple PBR Glass is, well, a glass shader. It was sort of a last-minute addition to the kit. It hit me that I often use a bunch of the same nodes when making glass shaders, which was the same impetus that created Simple PBR in the first place. So meet the refractive member of the family! It has built-in volumetric colors (absorption only! no performance worries here, I checked carefully!). It also will automatically switch to transparent shadows instead of caustics when roughness is set to 0, since Cycles can’t reliably produce caustics from sharp refractions. The “color density” input will adjust the strength of the absorption effect


Did you know that Cycles it getting support for Disney’s “principled BRDF”? It’s true: https://blenderartists.org/forum/showthread.php?403342-Cycles-Disney-Brdf
Once this is done it will more or less render obsolete all these community PBR shaders. There may still be a need for the glass and glaze shaders, it’s something I’ll look into when the time comes.


Finally, if you find Simple PBR useful, I’d appreciate if you could throw some coins in the tip jar in the sidebar



TECHNICAL MUMBO JUMBO SECTION

Ok, so what is actually new in v5? Here’s the important bits, I’ll explain why for each one:

  • Plain “Simple PBR v5” uses the new Multiscatter GGX glossy option in 2.78. This gives brighter, more correct results with high roughness. It comes with a bit of a noise and speed cost, hence the impetus for fastPBR, which uses the old simple GGX.
  • Diffuse roughness is now calculated as glossy roughness * 0.33 instead of using the glossy roughness directly. After actually reading some docs on Oren-Nayer shaders (how useful) I found that most real-world surfaces will not exhibit sigma values beyond 0.5, with most topping out around 0.3. This is something I probably should’ve remembered from my LuxBlend days… Anyway, I thought for awhile on the best way to handle diffuse roughness in Simple PBR. Using glossy roughness directly led to weird velvety-looks with roughness=1. I thought about disconnecting it, or locking it at a value, or exposing it as its own parameter. After awhile, I decided on using the glossy roughness * 0.33. It’s kind of arbitrary, but it gives a decent result in most cases without having to manually set it.
  • Simple fastPBR does not use Oren-Nayer at all, diffuse roughness is disconnected interally and set to 0. This gives a small speedup at the cost of realism on rough surfaces.
  • Roughness is squared in all cases. Most of the community PBR shaders, particularly Andrew Price’s, do this as it’s easier to work with and allows compatibility with most PBR authoring tools. This does mean it gives different results than a bare glossy BSDF, but I think most people will figure it out. Additionally, the roughness squaring is done as roughness*roughness, rather than roughness^2, just to be safe. This does not make a speed difference that I’ve ever observed, but why do things the potentially slower way?
  • Substance Painter export no longer packs roughness/metallic/height to an RGB texture. In 2.78, Cycles adds native support for single-channel textures (grayscale, float, scalar, single, whatever you want to call them). By exporting roughness and metallic into seperate grayscale files, they can be loaded using one channel each, meaning a total of 10 texture channels are loaded. Basecolor and normal both require 4, as Cycles does not have an RGB texture type, just RGBA. The old packed method required initializing a 3rd RGBA texture meaning 12 channels total. So the new method saves you 16.7% texture memory at the cost of making you load a 4th image node. (I recommend the “multiple images” option on the node wrangler addon, btw). Previously, seperate textures would’ve result in their own RGBA textures internally resulting in 16 channels, hence the intial design of the packed version. This is no longer needed.
  • You shouldn’t need to manually disable heterogeneous volumes or transparent shadows with the glass shader. I tested carefully to make sure these weren’t getting kick on when they weren’t supposed to, and there is no render time difference that I can pick up.
  • There is no fake caustics effect on the glass shader when roughness is 0. As far as I know, this can’t actually be done reliably in Cycles shader nodes. It would require modulating shadow opacity based on distance traveled along the vector to the light, and the vector to the light is not known when evaluating the graph. The “fake caustics” setups I’ve found all just fudge using some other vector which is not reliably correct, such as length along the eye path or viewing angle.

Sharing my compositor tools (Blender)

Using Blender’s compositor to post process your renders? Need a few shortcuts? I have some shortcuts. Below is a pack of 9 compositor node groups that will take care of various effects for you. There isn’t really any coherent organization to these, they’re just some node groups I use that I thought other people might find useful.

You can download it here:

Google Drive Link

The glare nodes:

There are 6 of these, all with the same general UI. They are all additive and easy to chain together.

Anamorphic Flare – A horizontal two-bladed spike flare. Reminiscent of the distinctive horizontal flares produced by anamorphic lenses. Horizontal flares are easy to compose and look cool, so they’re fairly popular to add some ‘umph’ to bright lights.

6-blade Flare – Works like anamorphic flare, but uses a more traditional 6-point pattern.

12-blade Flare – Adds a soft 12 point flare, meant to be used on top of the anamorphic or 6-blade flares

Glow – Uses the glare node’s “fog glow” mode to add an attractive bloom to bright objects. Bloom is a very useful effects as it’s one of the few lens distortions seen in both cameras and the human eye

Gauss Bloom – Another bloom node, using a gaussian blur instead of the glare node’s “fog glow” effect. Much faster to calculate, but the result isn’t as pleasing.

Ghosts – Uses the glare node’s “ghosts” mode to add a lens ghosting effect.
Controls:

Strength – Intensity of the flare. This is a scale factor before it is added to the image, so values over 1 are totally fine.

Saturation – Adjusts the final saturation of the colors relative to the original pixels.

Blur (not supported on fog glow) – Blurs the flare before adding it to the original render

Mask (not supported on ghosts) – Masks out regions so they do not contrbute to the flare.

Min Intensity (gauss bloom only) – The intensity of a pixel before it will flare. I wish this control was on all of them, but the glare node does not use an input for its “threshold” value.

Lens FX

The lens FX node adds various lens artifacts to the image, such as vignetting, barrel/pincushion distortion, and chromatic abberation. (note: the vignetting has some internal hardcoding for 16:9 images, you may need to crack open the node group as tweak this)

Controls:

Vignette color – The color to blend into the vignetted regions

Vignette blur – The softness of the vignette edges

Vignette strength – The ratio of vignette color vs original image.

Disotortion – Stregth of the lens distortion effect. Positive values create barrel distortion, negative values create pincushion distortion

Dispersion – Strength of the chromatic abberation effect

Luma Clamp

Because sometimes this is useful. This node will clip the value (calculated from HSV) to the given value. Please use with care, and note that the 1.0 value may be too low in many cases.

External Motion Vector

Blender has a kind of weird way of storing motion vectors, in that it encodes two keyframes into different channels. The vector blur node expects this, so it doesn’t behave properly with single-keyframe vector passes from other render engines such as Arnold. If you need to use that, just drop this node between your image node’s vector-pass output and the vector blur node. It will copy the red and green channels to blue and alpha, giving the vector blur node the data it needs.

Simple PBR v4

A newwe version of Simple PBR is available here: https://jtheninja.wordpress.com/2016/09/18/simple-pbr-v5/

The original post appears below:


Oops, I kept forgetting to post this. Awhile back, I made a note on the old Simple PBR that it had some mistakes in it, and this video by CynicatPro showed a better shader: https://youtu.be/pNiVB7tRG68

I also mentioned I had modified Simple PBR to take these things into account. At some point I mentioned I was going to post it, but kept forgetting to, Well, some people kept commenting to remind me, so, while I watch Bob Ross on Twitch, I’ve packed it up.

Say hello to Simple PBR v4 (no, I never posted v3, it was short lived).

~~~~UPDATE July 18 2016: I’ve modified the roughness calculation for diffuse slightly. This should give less wacky results. Same download link as before ~~~~

https://dl.dropboxusercontent.com/u/1706676/YouTube%20Summary%20Files/simple_pbr_v4.zip

Inside there you’ll find 4 node groups:

Simple PBR v4 – Simple PBR, which is sadly becoming a bit less simple internally, but it remains a simple metal/rough shader on the outside. This is the main shader, everything else is modifications of Simple PBR. It should work for metal and opaque dielectric surfaces.

Substance PBR v4 – Simple PBR v4, but with the roughness squared. This will make it play nice with roughness maps generated by Allegorithmic’s substance toolkit.

PBR Fresnel – a group of just the fresnel mask part. This is essentially the same as the group CynicatPro makes in his YouTube video. But it’s there if you need it (such as adding gloss to skin).

Substance Painter PBR v4 – name is a mouthful. Anyway, it’s Substance PBR v4, but with even more mods. It has a channel split and the normal map node integrated directly. It’s designed to be used with a Substance Painter export preset that is included in the bundle. That would be the “Blender Cycles.spexp” file. To install the preset, toss it in your Substance Painter shelf folder. See this doc on where to find that: https://support.allegorithmic.com/documentation/display/SPDOC/Creating+export+presets

Note that these groups will not behave properly with the normal input disconnected. If you are not using a bump or normal map, feed in the default normal from the texture coordinate or geometry nodes (either works).

_____

If you are not using Allegorithmic’s Substance tools, you can stop reading now. The rest of the post deals with integrating these shaders with the Substance twins.

The Substance Painter preset will generate 3 maps:

basecolor (nothing weird here)

“metalRough” – includes roughness in the red channel, and metalness in the green channel. The blue channel is blank.

normalOpenGL – Painter’s OpenGL Normal converted map. This map compiles your height and normal channels together with your baked normal map to create a single final normal map.

You will find corresponding inputs for each of these 3 maps on the Substance Painter PBR v4 node group. Just plug them in, and change the normalOpenGL and metalRough to non-color data (this is important, they will not work correctly as “color”). Don’t worry about adding a normal map node or splitting metalRough’s red and green channels, the node has all of that built in, then passes it to Simple PBR. Just import your textures, set non-color data on metalRough and normalOpenGL, attach them to the group, hook the group to your mat output. Nothing else to it!

Screenshot 2015-10-30 22.21.59

Remember that Substance Painter exports PNG files as 16bit, which Cycles will import as float textures. These use more memory, and if you’re rendering on an Nvidia card, you can only have 5 in your scene. Rendering on AMD? Well, you get zero. This has nothing to do with the Simple PBR shaders, just something you should be aware of. You can use a format that is 8bit in Painter, like Targa. Or just live with it.

Cycles scene optimizations: Ray visibility

If you want to make something invisible to a certain ray type in Blender/Cycles, most people do things like this:

Screen Shot 2015-02-21 at 7.24.15 PM

STOP DOING THAT.

You are making Cycles waste time doing worthless calculations. Instead, go over to the object tab, and use these instead:

Screen Shot 2015-02-21 at 7.27.14 PM

Unchecking “camera” there will produce the exact same result (the object is invisible when viewed directly, but otherwise appears normally), but it goes about it differently. The shader node setup tells Cycles when evaluating the material, figure out the current ray type, and if it’s camera, choose the second input on the mix shader. This is a transparent BSDF node at full white, so the ray passes unchanged.

Ray vis does it a much more efficient way: it just tells Cycles “if the current ray is a camera ray, don’t even bother checking if you hit this object, just assume you didn’t”. This is important, as it allows us to filter out the object while doing intersection tests (render nerd speak for “checking to see what the ray hit”). Even better, it allows us to avoid running the shader at all, much less realizing the result was a transparent BSDF and having to continue the path and do the whole thing over on the next object we hit.

It gets worse though. The light path shader includes a transparent BSDF, thus, it enables transparent shadows. Realtime engines and rasterizers have taught too many people to think alpha maps are their friends. But raytracers are different: to them alpha maps are evil, because they create a horrible effect called transparent shadows. Raytrace shadows are computed by tracing a path from the shading point (that’s where the initial ray landed) out to a lamp, and seeing if anything blocks the path. If something is there, the object is “in shadow” and the lamp contributes nothing. If it has a clear shot, it is not in shadow, and the lamp contributes at full strength. Simple.

Transparent shadows crap all over that simplicity. They cause the shadow ray test to return bullshit like “the ray might be blocked, or maybe it isn’t”. The only way to find out is to to run the shader (which we didn’t even have to do in the first place for opaque shadows!) and figure out what the actual opacity is at the point on the object we hit, then trace another ray from this point to see if we were actually blocked entirely by something else and we did all this for nothing (lolz). God help you if that “something else” is also transparent, then we have to do this shit all over again.

Needless to say, that wastes a lot of time. And now you know why that “transparent shadows” box is in the material options. Unchecking that tells Cycles “I know this mat has a transparent BSDF, but just ignore that and do opaque shadows anyway”. Because that can save a lot of time if no one is going to notice an object is casting solid shadows.

Now, sometimes we don’t have a choice, (alpha maps have their uses), but in the case of 100% transparency to a particular ray type, we do. We can just turn off ray visibility for that type, and have a simple shader with no transparency.

Just to compare, I set up this scene. The cube is invisible to camera rays:

Screen Shot 2015-02-21 at 7.42.18 PM

Regardless of if we use ray visibility or the light-path shader, the result is the same. But the render times aren’t:

  • Diffuse-only shader, camera ray visibility disabled: 1.73sec
  • Diffuse/transparent mix by “is camera ray”, camera ray visibility enabled: 2.28sec
  • Diffuse/transparent mix by “is camera ray”, camera ray visibility enabled, but “transparent shadows” disabled: 2.10sec

This is obviously a worst-case scenario, but you can see the impact of the extra calculations. 30% longer to render the exact same image! Using the same setup with transparent shadows disabled (still the same result, because light path “is camera ray” will never evaluate to 1 for a shadow ray) is only 2.1 sec. That’s means about 35% of that penalty wasn’t even due to our extra shader stuff, it was due to the useless enabling of transparent shadows.

So there we have it. Ray visibility is your friend.

_______

“But wait!” you might be saying, “I need to do some ray-switching for a bunch of objects with this one material! Light path is a lot easier in this case!”

Python to the rescue. This will disable camera visibility on all selected objects (select one object, then use “select > linked > material” to grab all objects with your mat):

import bpy

for obj in bpy.context.selected_objects:
    bpy.context.scene.objects.active = obj
    bpy.context.object.cycles_visibility.camera = False

If you need to flip a different ray visibility switch, you can just change that last line. This version will turn on transmission visibility:

import bpy

for obj in bpy.context.selected_objects:
    bpy.context.scene.objects.active = obj
    bpy.context.object.cycles_visibility.transmission = True

The python names for the 6 switches are:

camera
diffuse
glossy
transmission
scatter
shadow

Importing Substance Painter texture to Cycles

You should also check out the latest version of the PBR node group here: https://jtheninja.wordpress.com/2016/09/18/simple-pbr-v5/


 

Substance Painter is a powerful physically-based (PBR) texturing tool. It’s primarily aimed at game use (for now…), but you can easily make use of its output in Cycles. In this tutorial, I’m going to show you how to do that.

To start, I’ve given everyone’s favorite monkey an interesting paint job using the default color, height, roughness, and metallic channels.

suzanne

First order of business is to export these for Blender. Hit File > Export, and just use the default “Document Channels + Normal” preset.

export channels

Now let’s look at our shader in Cycles. We’ll start by making the simplest, most standard physical shader, a diffuse/glossy mix with fresnel.

starting nodes

NOTE: Some people like to use the layer weight node instead of the fresnel node. If that’s you, go right ahead. I’m just using the fresnel node here for simplicity.

Base Color

Our first channel to deal with is base color. There’s not much to this one. We have a base color image, we’ll just load it and plug it into the diffuse BSDF’s color slot.

base color attatched

Roughness

Our next texture if the roughness map. As you might have guessed, we’re connecting it to the roughness inputs on both the diffuse and glossy nodes. However, there’s a couple things we need to set to make sure Cycles interprets the map correctly. The first is to change the node from “color” to “non-color data” (as that is what the roughness map is). Any channel that is not set as “sRGB” in substance painter should be loaded as non-color data. Here we see that base color is sRGB (and thus should be loaded as color), but the rest of our channels are luminance (marked with an “L”), so they should be loaded as non-color data.

sp channel type

The other thing we need to do is square the roughness value to match the range between SP and Cycles. To do that, add a math node, set it to “power”, connect your roughness map to the top slot, and set the bottom slot to “2.0”.

rough attached

Let’s check how it looks so far:

color_rough_monkey

Ok, it’s a start. The colors are right at least. Now let’s deal with that height channel. There’s a few different ways to do that:

Height Method 1: Bump Node

One obvious way to handle the height channel is to do what SP shows it as: load the height texture and stick it in as a bump map. To do that, we’ll pass it through the bump node and attach that to our normal inputs

bump node

This works ok, but you often need to fine-tune the bump strength, and if you have a normal map for your object, we have to add more spaghetti (and load another texture) to integrate the two. There’s a better way, namely…

Height Method 2: The Normal OpenGL output

Substance Painter can generate a number of “converted” texture maps. One of which is the “Normal OpenGL” channel, which generates an OpenGL-style tangent-space normal map using the height channel and the object’s normal map (if it has one). We can attached it with the normal map node, like usual.

normal ogl node

Let’s try that:

normal_monkey

Perfect! Works right out of the box! In this case, our object didn’t have a baked normal map in Substance Painter. But in case it did (such as baked sculpting detail) the normal map will contain that as well as your height painting, so you don’t need to do anything else to connect the two.

Optional Height Method 3: The Displacement Output (Which Doesn’t Work Right)

There’s one more method you can do. It doesn’t really behave the way it should since it relies on an unfinished feature in Cycles, but you can instead attach the height map to the displacement output. If you don’t turn on experimental features, this has basically the same result as the bump node method. However, if you enable experimental and change the displace mode to “both” (aka, auto-bump), Cycles will displace the vertices of the mesh as best it can to fit the height map, then adjust the normals to fit the rest of the way.

It’s kind of cool, but again, this is an UNFINISHED FEATURE of Cycles that DOES NOT WORK QUITE RIGHT. (don’t enable subdiv, trust me). It’s probably best you just forget I mentioned this and use the normal map method.

Metallic

Ok, one more channel. This one gets a bit complicated. Up until now, our shader has been a simple dielectric shader. We now need to introduce an alternate shading path for metal, and use the metallic map to blend between them. To do this, you are going to add a mix node at the end of the chain, attach your metallic map to the mix factor, then put an extra glossy BSDF on the second input, and attach your base color, rough (from the power node) and normal (from the normal map node) to this glossy BSDF.

metallic attached

I’ve highlighted our newly added nodes in red. Areas that are dark in the metallic map will use our diffuse/glossy fresnel mix we created earlier. Areas that are bright in the metallic map will shift over to this glossy-only shader. Since metals have colored reflections, we attach the base color to the glossy-color input here, unlike our other glossy BSDF on the dielectric side. Since roughness and normals are shared, we use the squared-roughness and normals just like on our other BSDF nodes.

Wrapping Up

Here is our final monkey!

final_monkey

This shader setup is just the very basic elements required to translate the shader. There are numerous other effects you can add. For example, some people like the look of metal shaders that blend two glossy BSDFs at slightly different roughness. You can add that in to your shader (use an extra math node to scale your roughness map). Some people prefer to use the layer weight node instead of fresnel. It’s all up to you, feel free to experiment!

You can make a node group out of your shading nodes here (minus the image textures) so you don’t have to set this up all over again for every material. Or you can just use mine. Grab it in this post: https://jtheninja.wordpress.com/2016/09/18/simple-pbr-v5/

Simple PBR v2

Update 8/30

Simple PBR contains mistakes. You should build something based on this tutorial (by the excellent cynicatpro) instead: https://youtu.be/pNiVB7tRG68

I have an updated version of Simple PBR I can post if people are interested.

 

UPDATE 2, 10/30:

Updated version is here: https://jtheninja.wordpress.com/2015/10/31/simple-pbr-v4/


 

Now that I’ve gotten a chance to test things out in the Ruined Fountain scene, I can now pass out the much-improved version of Simple PBR:

https://dl.dropboxusercontent.com/u/1706676/YouTube%20Summary%20Files/simple_pbr_v2.blend.zip

Simple PBR is now even simpler! It now (properly) uses the albedo/rough/metal model used in many newer renderers and game engines.

It also comes with a cousin, Substance PBR. Substance PBR is just Simple PBR with the roughness squared, this is necessary to match the roughness curve used in Allegorithmic’s Substance tools. (bitmap2material, substance painter, etc). Substance PBR should more or less completely match the Substance pbr_metal_rough viewport shader, so you can just bake map channels, plug them in, and go. (I’ll have a more detail blog post in the coming days on how to work with Substance and Blender)

There is also a third group, Simple PBR Spec. This is like Simple PBR, but uses the spec/gloss model instead of metal/rough.

These groups do not have any tools for texture baking/creation, you still need to make those on your own. You may wish to check out Allegorithmic’s excellent guides on the subject: https://www.allegorithmic.com/pbr-guide