Comparing albedo map creation techneques

In this post I am going to be looking at some different methods of producing albedo maps from a photograph for use in a PBR material system. For these tests I will initially be comparing the possible techniques such as using Photoshop to manually create the map, as well as semi-automatic creation though using software such as ShaderMap. To actually get a good idea of what results are possible I am going to be looking at a variety of materials types.

Test 1: Wood

Results

Using the manual method kept more of the dark information such as the cracks. This could probably be made better with a little more work to balance levels, however this may be a desired look for the material type.

The ShaderMap results have more colour variation as the dark areas are better filled with colour information which better fits the definition of an albedo map.



Conclusion

Close up the difference in dark areas can be seen, but at a further distances the difference is barely noticeable. Other than the dark notch detail which looks washed out in the ShaderMap version, the maps look very similar to each other but for the use of this texture I do prefer the results of the manual process.

Future tests

• Brick
• Fabric
• Ground

Unreal Engine 4 environment creation

Landscape and terrain

Setup

Unreal Engine 4 environment creation playlist - https://www.youtube.com/playlist?list=PLPTQEHtBC4vkIXU8QpfMCtepPJOp19VOe


Landscape painting

Creating Landscape Materials - https://docs.unrealengine.com/latest/INT/Engine/Landscape/QuickStart/4/index.html

RATSGAME UE4 Landscape Materials playlist - https://www.youtube.com/playlist?list=PL2G_ecHWhZBmEQih1qfe4yIzY49tKxST6


Terrain creation (advanced version of landscape)

Rather than using Unreal Engine's landscape system it is possible to create a terrain which can be thought of as a large geometry mesh which can have materials applied almost like any other mesh. This mesh can be divided up to allow using of techniques such as LOD. World Machine (http://www.world-machine.com/) is a great tool for creating/generating terrain that can be imported into UE4.

Weight maps can be used to control how materials are applied to the terrain. They are quite low resolution, but in combination of using height maps the materials can be blended together more naturally.

GDC 2015: Creating the Open World Kite Real-Time Demo in Unreal Engine 4 - https://www.youtube.com/watch?v=clakekAHQx0


Lighting and Shadows (WIP)

Lightmass Global Illumination
https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/Lightmass/index.html

Ray Traced Distance Field Soft Shadows
https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/RayTracedDistanceFieldShadowing/index.html

Distance Field Ambient Occlusion
https://docs.unrealengine.com/latest/INT/Engine/Rendering/LightingAndShadows/DistanceFieldAmbientOcclusion/index.html

Unreal Engine 4 Twitch Broadcast - Soft Shadows & Subsurface Scattering - https://www.youtube.com/watch?v=DQt_OopZadI

Places to look for important settings/features

Lightmass Settings in World Settings
Static Lighting Level Scale - lower value = more contrast/deeper shading

SkyLight

• Light and Distance Field Ambient Occlusion tabs
• sky distance threshold to 1
• uncheck the low hemisphere is black (to get some fake "bounce light" from the ground)

Foliage (WIP)

Overview

When creating foliage it needs to be thought of and split into 2 sets:

1. Foliage - normally larger objects like tress and rocks that have collision which are manual or procedural placed
2. Grass/Vegetation - smaller objects like grass, flowers and pebbles that have no collision and placed through material placement

Setup and Creation

My recommend tool is Speedtree for UE4 (http://www.speedtree.com/ue4/) allows semi-automatic generation of foliage such as tress and bushes, but manual creation for grass by simply applying textures to polygon planes.

Creating Models For UE4 (SpeedTree) - http://docs.speedtree.com/doku.php?id=creating_models_for_ue4

Unreal Engine 4 foliage creation playlist - https://www.youtube.com/playlist?list=PLPTQEHtBC4vlTDRf_YPQNThOHa_EeU2BC

Advanced features

To get the best results on foliage I enable Distance Field Ambient Occlusion and update the following settings on the mesh's Build Settings (hidden drop down under each LOD in the asset viewer):

• Enable Generate Distance Field as if Two Sided
• Increase Distance Field Resolution Scale to improve AO quality

The slider on the left shows the difference when Generate Distance Field as if Two Sided option is toggled and the left slider shows the difference when Distance Field Resolution Scale is increased which brings back some of the depth lost when enabling the two sided option. I found that values above 5 did not really increase visual quality, but did massively increase the time taken to generate the distance fields.

NOTE: you must enable the option for instanced foliage if you want to paint foliage or use the procedural foliage spawner system. This can be found in the Modes window under the Foliage tab, after selecting a foliage type, scroll down to the Instance Settings rollout and check the option for Affect Distance Field Lighting. This does need to be done for each foliage type which will use DFAO.

Examples

UE4 - Forest - https://www.youtube.com/watch?v=3loi-2Bx72A

UE4 SpeedTree Forest - https://www.youtube.com/watch?v=dsniFiDS1lk

UE4 - SpeedTree - DFAO/GI test - https://www.youtube.com/watch?v=slc--V2pi5c

UE4 SpeedTree dynamic day cycle - https://www.youtube.com/watch?v=AphIofwFnUU

[FREE] Foliage Starter Kit - https://forums.unrealengine.com/showthread.php?59812-Free-Foliage-Starter-Kit


Creating roads, paths, fences etc

Landscape Splines - https://docs.unrealengine.com/latest/INT/Engine/Landscape/Editing/Splines/index.html

DokipenTechTutorials Unreal Engine Spline Road Tool Tutorial playlist - https://www.youtube.com/playlist?list=PLHadbgEqCTxDgj-RwPQGkaUypb05NJYN6


Water

Water Surface Overview in UE4 - https://wiki.unrealengine.com/Videos/Player?series=PLZlv_N0_O1gYq4tiS45UAgghUxoF916rH

Gaming and Engine Tutorials Water Tutorials Unreal engine 4 playlist - https://www.youtube.com/playlist?list=PLd2rY36Ym3b8Iqc8Ji7indM4oaLv_l2UT


Level building

Building the Glass Walls (v4.7) - https://wiki.unrealengine.com/Videos/Player?series=PLZlv_N0_O1gak1_FoAJVrEGiLIploeF3F&video=xzGWuW_iWPM

Examples

Creating a quick Unreal Engine 4 desert scene - https://www.youtube.com/watch?v=MlgvfEicdwU

Creating a quick Unreal Engine 4 Night/Lake Scene - https://www.youtube.com/watch?v=FRxnKYy62KE

Creating a quick Unreal Engine 4 Valley Scene - https://www.youtube.com/watch?v=GgwtME_WhXI


Other tips

Adding Atmospheric fog to enable light shafts - https://docs.unrealengine.com/latest/INT/Engine/Actors/FogEffects/AtmosphericFog/index.html


Good examples of environments and levels developed in UE4

Breaking Bad Cabin Environment [UE4] - https://vimeo.com/101387734

Unreal Engine 4 - Ghosts'N Goblins - https://www.youtube.com/watch?v=grJZEVRx2vY

UE4 - Trailed - Walkthrough - StudentProject - NAD - https://www.youtube.com/watch?v=iEkl-h3e6Us

P.T. recreated on Unreal Engine 4 - https://www.youtube.com/watch?v=UKiy2Pwp8Ek

UE4 - Snow 2 by koooolalala - https://www.youtube.com/watch?v=E-FpKzD9_uM

UE4 - Forest by koooolalala - https://www.youtube.com/watch?v=3loi-2Bx72A

Understanding and adapting to a Physically Based Rendering (PBR) workflow

So Physically Based Rendering (PBR) is here in a big way with Unreal Engine 4, Unity 5, Quixel Suite 2 and Marmoset Toolbag 2 but a few to name that now use this workflow as standard. It's quite a lot to take in, but not too hard to understand once you get going with it. Rather than try to explain what the differences are and what you need to do to adapt, I think it's more useful to just list the materials I found while learning this new workflow, as there's others out there that have already done that job.

Reading material

Physically Based Rendering Encyclopedia - https://docs.google.com/document/d/1Fb9_KgCo0noxROKN4iT8ntTbx913e-t4Wc2nMRWPzNk/edit

The above link covers most of the other materials I have read and listed below but it's also worth reading the rest as it may cover different tools and techniques in your own workflow.

Physically Based Rendering in Substance - https://www.youtube.com/watch?v=LP7HgIMv4Qo

Allegorithmic PBR Guide Playlist - https://www.youtube.com/watch?v=mnJ8NjLRmLk&list=PLB0wXHrWAmCwwpWr5aZ1lf0wY3IcWJAjE

Texture Maps Explained - PBR Workflow - https://www.youtube.com/watch?v=PjGCtnEDDeU

Physically Based Texturing - https://www.youtube.com/watch?v=Tt30zzBQb3w

Tutorial: Physically Based Rendering, And You Can Too! - http://www.marmoset.co/toolbag/learn/pbr-practice

Basic Theory of Physically-Based Rendering - https://www.marmoset.co/toolbag/learn/pbr-theory

Tutorial: PBR Texture Conversion - http://www.marmoset.co/toolbag/learn/pbr-conversion

Allegorithmic - The Comprehensive PBR Guide - https://www.allegorithmic.com/pbr-guide

Physically Based Materials (Unreal Engine 4 documentation) - https://docs.unrealengine.com/latest/INT/Engine/Rendering/Materials/PhysicallyBased/index.html

PBR Texturing Techniques - http://quixel.se/dev/issue03

Textures

gametextures.com
Offers a library of ready to use maps for use in a PBR workflow. Although not free, at the time of writing they do offer a 14 day free trial which includes 75 or 200 material downloads which is very generous and helps you get started with this new workflow and for $19 and $30 per month after that it seems like a fair deal.


Tools

gametextures.com workflow converter - https://www.gametextures.com/gametextures-to-metalness-a-new-tool-to-convert-workflows/

Allows you to take a set of maps from alternative workflows and convert for use in PBR. This is not just a plug everything in and hit convert process though. You will need to provide the required inputs to get good results and spend some time tweaking.

gametextures.com drag and drop Substance system - https://www.gametextures.com/how-to-import-gametextures-substances-into-ue4-and-unity-5/
The website now offers downloads of substances which can be quickly imported into Unreal Engine and Unity via drag and drop.

Need to create extra texture maps?
If you have a normal map then NDo has a built in feature to take a normal map and output a variety of different maps including AO, height, specular and cavity - http://quixel.se/usermanual/quixelsuite/doku.php?id=convertmenu

For the workflow converter you will also need a gloss map. These are easy enough to produce and this video shows the basic procedure - How to create a gloss map from a diffuse map https://www.youtube.com/watch?v=OKdUIm3i_jc


Workflow Tips

Albedo map creation

Manual process using Photoshop

How to Make an Albedo Texture from a Diffuse Texture - https://www.youtube.com/watch?v=KKQZN3eoKUo

Process steps:

1. open diffuse map
2. create a duplicate layer of the diffuse map. ensure the new layer is above the original
3. fully desaturate (CTRL + U or add an adjustment layer) the duplicated layer to create a cavity map
4. invert (CTRL + I) the duplicated layer, so that dark areas now show as light
5. change blending mode of the duplicated layer to Soft Light
6. make any changes to saturation etc of original map (if required)
7. using the luminosity values chart below select the value most appropriate to the type of material
8. open the histogram and ensure the expanded view is selected by clicking the arrow and four lines in the top right of the window and set Channel to Luminosity in the drop down
9. take note of the median value
10. adjust the levels (CTRL + L or add an adjustment layer) of the original map (or the overall new texture) so that the median level comes close to the luminosity value from the chart

Semi-automated process using ShaderMap

Creating an Albedo Map from a Photographic Texture - http://shadermaptutorials.com/tutorial/creating-an-albedo-map-from-a-photographic-texture/

Luminosity value guidelines

Material            Linear value  sRGB value  photoshop    source          
                                              median value
Brushed Metal       0.02          0.16                     [2]
Charcoal            0.04          0.22                     [1]
Fresh asphalt       0.04          0.22                     [1]
Rubber              0.04          0.23                     [2]
Black acrylic paint 0.05          0.25                     [3]
Coal                0.05          0.25                     [2]
Leaves              0.05          0.26                     [2]
Rust                0.06          0.27                     [2]
Plastic (glossy)    0.10          0.36                     [2]
Painted metal       0.12          0.38                     [2]
Rough steel         0.13          0.40                     [2]
Worn asphalt        0.12          0.38                     [1]
                    0.15          0.42                     [3]
African tanned skin 0.15          0.42                     [3]
Bare soil           0.17          0.44        112          [1]
Dirt                0.17          0.45        115          [2]
Plastic (rough)     0.19          0.48                     [2]
Brick/Concrete      0.23          0.51                     [2]
Dry clay soil       0.23          0.51                     [3]
Mud                 0.23          0.52                     [2]
Green grass         0.25          0.53                     [1][3]
Plaster             0.25          0.54                     [2]
Canvas              0.27          0.56                     [2]
Old concrete        0.30          0.57                     [3]
Wood                0.31          0.59                     [2]
Red clay tile       0.33          0.60                     [3]
Rock                0.33          0.61                     [2]
Desert sand         0.40          0.65                     [1][3]
Satin               0.43          0.69                     [2]
New concrete        0.50          0.72                     [3]
New concrete        0.55          0.76                     [1]
Clean cement        0.55          0.76                     [3]
Ceramic             0.57          0.78                     [2]
Ocean Ice           0.50–0.70     0.73-0.85                [1]
White cement        0.70          0.85                     [3]
White acrylic paint 0.80          0.90                     [3]
Fresh snow          0.80–0.90     0.90-0.95                [1][3]

Notes:
some values converted using https://docs.google.com/spreadsheets/d/1KcHvNFqQA8Y7xyjMTuuQgMTT3bB6lvNpTgpsU1MmDjs/edit#gid=0

Sources:
[1] https://seblagarde.wordpress.com/2011/08/17/feeding-a-physical-based-lighting-mode/
[2] http://www.marmoset.co/toolbag/learn/pbr-practice
[3] https://www.fxguide.com/featured/game-environments-parta-remember-me-rendering/