Getting en creating assets

Creating assets from with pictures. Meshroom

To optimise your asset, you could use Proxy Geometry Tool?

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Optimisation tutorials general

Culling methods

Using the proxy geometry tool

Notes from the video above

  • Doing too much
  • Content Developer Accountability
  • Blueprint
  • Platforms
  • Granularity
  • Fighting the Tech
  • Using Epic’s Support Structure

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Tutorials and notes on vectors

Documentation vectors

Documentation splines

Documentation transforms

Documentation transformation

Documentation Spline Mesh

Set end offset

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Basic commands in editor

  • Culvert at dike
    To discharge water from island to sea
  • Pumping station with pipes
    To discharge water from island to sea
  • Ditches
  • Discharge water to Pumping-station of culvert at dike
  • Weirs
    To control waterlevel ditch
  • Culvert in ditch
    When ditch has to cross road
  • Lakes / surface water
    For storage of surplus of rainfall
  • Sewer pipe
  • Storage settling basin (BBB)

The dynamic water system on land is programmed as a blueprint.
FD_Surfacewater contains both the logic and the assets of the water system. The backbone of the FD_Surfacewater  is a spline with points. The points represent a change in the water system, for example: input discharge, different structure (pipe, channel, weir..), different dimension. So each point (=Node) is connected with the database WaterSystemData. So in between 2 points (=branch) of the backbone spline, everything is the same, based on the information of the downstream point.. Spline and point represent the bedlevel of the structure.
Index 0 spline is downstream

Al the programming is done in the so called construction script. This is a cool feature of Unreal Engine.  Al programmed calculations can be done in the editor. It is for example not necessary to run the game, to see what waterlevels will occur. They are already calculated in the editor.

Formulas used for calculation water levels

Some general Notes:

  • The basis of the watersystem is a spline. Between 2 nodes the structure is the same. The location of the spline is the bedlevel.
  • FD_Surfacewater  is one line with no branches and has a fixed direction of flow.
  • A dendritic system is possible, because the 3D world may contain different FD_Surfacewater  which are connected at points. When calculation a dendritic system the sequence of making calculations is important.
  • Strategy for calculating the water-system.We assume a stationary flow. So new calculations are only made when changes are made to the water-system. In the future calculations will be made per time-step and change in storage will also be taken into account.
    Link to page with formulas used
  • To get access to the information, or to change information menu are used.
    Link to page Navigation
  • Internal Unreal uses centimeters, the
    FD_Surfacewater uses m
  • Backbone of FD_Surfacewater is the WaterDataStruct which stores all data (also calculated data) for each branch.

Connect side branches

  • Information on side branch is stored in [ConnectionLeft] and/or [ConnectionRight]
  • In FD_GameMode: FD_WaterSystemsref and FD_WatersystemName. Note This does not work in constructionscript ? So it should be a separate function in the constructionscript.
  • New function Find_Side_Branches
  • Changed variable InputDischarge to a 2dvector. x = de input branch, y is the input from sidebranches

Design Manhole / Sewer

  • If 2 pipes don’t have the same bedlevels, the difference in height is stored in With_Diameter_m.y. Adding this height is only applied the x downstreampoint
  • Manhole is not a separate branch, but is generated when 2 culvert pipes branches connect.
  • The check on manhole is made when type is culvert. If type_down also is a culvert, a manhole can be added.
  • Switch to add manhole is :
    When diameter pipes is different, manhole is added automatically
    When diameter pipes are the same, the following switch is used.
    Slope X = 1 add manhole, Slope X = 0 no manhole  
  • A Boolean variable Manhole  is defined.
  • Manhole is always a rectangle, with max 4 pipes connected.  So 2 other BP_watersytems could be connected to the manhole.
  • Alle dimensions in m
  • When function manhole is activated the following information is defined:
    – bedlevel, based on 4 connections
    – D1, D2 (left), D3, D4(right)
    – Width manhole based on D1 and D4.  Width = Max D1 / D3 + 0,6 m
    – Length manhole based on D2 en D4. Length = Max D2 / D4 + 0,6 m
    – Length manhole / 2 = reduction length (m)
    – Surfacelevel is de highest surfacelevelworld of the 4 connections
  • Manhole is activated before the pipe is drawn. This because the reduction length.
  • Information from the array is also necessary for the Reduction Length for ending and starting pipe.

Design weir

  • Exists of 3 parts, left – middle (=crest) – left
  • Width_Diameter_m.x = width weir.
  • Width_Diameter_m.y = width sides

Blueprints used:

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List of the different water-systems on the island.  Wil be used for the instructural design, design island and assets

First attempt to build a water system in Unreal

  1. Waves at sea
  2. Tide at sea
  3. Currents at sea
    Erosion of beach
  4. Culvert at dike
    To discharge water from island to sea
  5. Pumping station with pipes
    To discharge water from island to sea
  6. Rainfall
    Is main source for supply of freshwater on the island
  7. Seepage
    From island to sea.
    From sea to groundwater.
  8. Groundwater
  9. Drainage pipes
  10. Ditches
    Discharge water to Pumping-station of culvert at dike
  11. Weirs
    To control waterlevel ditch
  12. Culvert in ditch
    When ditch has to cross road
  13. Lakes / surface water
    For storage of surplus of rainfall
  14. Sewer pipe
  15. Infiltration
    Infiltration sewer, Wadi, infiltration box, infiltration box
  16. Storage settling basin (BBB)
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Tutorials Materials / Shaders

I find the most difficult.


Albedo is the characteristic color of an object. More precisely, it is the bi-hemispherical reflectance of a surface. It is view independent and is more commonly named diffuse.

Reflection = on the surface

Diffusion = Out of the material ( Diffuse Light”, “Diffusion”, “Subsurface Scattering” ) . The absorption and scattering of diffuse light are often quite different for different wavelengths of light, which is what gives objects their color (e.g. if an object absorbs most light but scatters blue, it will appear blue). The scattering is often so uniformly chaotic that it can be said to appear the same from all directions – quite different from the case of a mirror!

Translucency & Transparency = different diffuse colour at different depth material? Skin for example.

Energy Conservation : reflection and diffusion are mutually exclusive.

Metals: Electrically conductive materials.
Firstly, they tend to be much more reflective than insulators (non-conductors). Conductors will usually exhibit reflectivities as high as 60-90%, whereas insulators are generally much lower, in the 0-20% range. These high reflectivities prevent most light from reaching the interior and scattering, giving metals a very “shiny” look.

Secondly, reflectivity on conductors will sometimes vary across the visible spectrum, which means that their reflections appear tinted. This coloring of reflection is rare even among conductors, but it does occur in some everyday materials (e.g. gold, copper, and brass). Insulators as a general rule do not exhibit this effect, and their reflections are uncolored.

Finally, electrical conductors will usually absorb rather than scatter any light that penetrates the surface. This means that in theory conductors will not show any evidence of diffuse light. In practice however there are often oxides or other residues on the surface of a metal that will scatter some small amounts of light.

Fresnel: refers to differing reflectivity that occurs at different angles.
Specifically, light that lands on a surface at a grazing angle will be much more likely to reflect than that which hits a surface dead-on. This means that objects rendered with a proper Fresnel effect will appear to have brighter reflections near the edges.

The first is that for all materials, reflectivity becomes total for grazing angles – the “edges” viewed on any smooth object should act as perfect (uncolored) mirrors, no matter the material. Yes, really – any substance can act as a perfect mirror if it is smooth and viewed at the right angle! This can be counterintuitive, but the physics are clear.

The second observation about Fresnel properties is that the curve or gradient between the angles does not vary much from material to material. Metals are the most divergent, but they too can be accounted for analytically

There is one big caveat for the Fresnel effect – it quickly becomes less evident as surfaces become less smooth

Microsurface: Most real-world surfaces have very small imperfections: tiny grooves, cracks, and lumps too little for the eye to see, and much too small to represent in a normal map of any sane resolution. Despite being invisible to the naked eye, these microscopic features nonetheless affect the diffusion and reflection of light. Microsurface detail has the most noticeable effect on reflection (subsurface diffusion is not greatly affected and won’t be discussed further here)

This measure is often referred to as “Gloss”, “Smoothness”, or “Roughness”.

When the equations are properly balanced, a renderer should display rough surfaces as having larger reflection highlights which appear dimmer than the smaller, sharper highlights of a smooth surface. It is this apparent difference in brightness that is key: both materials are reflecting the same amount of light, but the rougher surface is spreading it out in different directions, whereas the smoother surface is reflecting a more concentrated “beam”:

Further, an investigation of real world materials will show that reflectivity values do not vary widely

Microsurface properties have other subtle effects on reflection as well. For example, the “edges-are-brighter” Fresnel effect diminishes somewhat with rougher surfaces (the chaotic nature of a rough surface ‘scatters’ the Fresnel effect, preventing the viewer from being able to clearly resolve it). Further, large or concave microsurface features can “trap” light – causing it to reflect against the surface multiple times, increasing absorption and reducing brightness. Different rendering systems handle these details in different ways and to different extents, but the broad trend of rougher surfaces appearing dimmer is the same.

Screenshot from Vertex painted Flowmaps

Material World Position


Notes with the video

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Fluid Dynamics Formulas

General assumptions

  1. Flow is turbulent.
    So formulas of Manning, Chezy and Darcy-Weisbach can be used.
  2. Flow is sub-critical.
    So calculations of water-levels start downstream and goes upstream. At weirs super-critical flow may occur.
  3. Flow is steady
    Discharge is not changing rapidly. Of-course over time discharge (and thus water-levels etc) can change.
  4. Sea is salt water, on the island fresh water
  5. There are two main watersystems. The watersystem on the island and the sea (waves, tide, current). The connection between the two are by the culvert in the dike and seepage. High tide in combination with low water level on the island could make water flow from sea to the island. High tide can cause seepage to the land, low tide seepage to sea. Maybe in high tide in combination with big waves can cause water flowing over the dike to the island.
  6. Water enters the systeem by: rainfall and seepage.
  7. Water leaves the island through : Culvert in dike, pumping station, seepage and evapotranspiration.
  8. System is dendritic.
    So water has one direction to flow.

Calculations in FD_watersystems

  • For each branch waterlevel (ylevel) and Energylevel (Hlevel) are calculated at the beginning (.x) and end (.y) of the branch. This info is stored in WatersystemData.
  • Hlevel.x = Hlevel.y downstream branch.
  • yLevel.x = yLevel.y downstream branch. Consequence of this strategy is that when there is a significant change in dimension or discharge, a short branche is needed. In this short branch the transfer between the 2 different velocityheads takes place. With change in discharge this short branch is located downstream, with change in dimension this short branch is located upstream
  • Weir is an exception. Hlevel.x is calculated based on the crestlevel.
  • Over the length of a branch, the basic dimensions are the same, only the surfacelevel at x and y may differ. Exception is the connector, you have different width and slope downstream and upstream!!
  • CulvertRectangle: If downstreams  waterdepth < Height culvert : Type is converted to Trapezium. Note: With high velocities, water level will rise and the type maybe should be concerted back to culvertrectangle. This can be solved by splitting het culvert in several branches.
  • In a branch (between 2 points) discharge is always the same. 
  • 2 special branches when calculating. First is the outflow: Discharge = 0. Value in InputDischarge.x is the velocity in the receiving water. Second is the weir : There is a jump in HlevelWorld compared to the downstream waterlevel.
  • Weir is always assumed as free flow.  And as a short crest. Waterlevel .x and .y are the same.
  • Based on ylevel.x. Slope Hline is calculated. Hlevel.y is calculated.

Workflow calculation

In the case of type = trapezium

  1.  HlevelWorld_m.x = HlevelWorld.y previous branch
  2. yLevelWorld_m.x = yLevelWorld.y previous branch 
  3. Get Discharge from point upstreams
  4. Calculate Depth_m.x ,WettedArea.x, WetterPerimeter.x, HydraulicRadius.x, Velocity.x
  5. Calculate Hslope, dH, Time
  6. HlevelWorld_m.y = HlevelWord_m.x + dH
    ylevelWorld_m.y = yLevelWorld,x + dH
  7. Calculate Depth_m.y ,WettedArea.y, Velocity.y, VelocityHead
    ylevelWorld_m.y= HLevelWorld_m.y – VelocityHead
  1. Outflow down-streams is calculated separate
  2. Check if branch is weir. If weir calculate H above weir, convert to HlevelWorld_m.x = HlevelWorld.y.  yLevelWorld_m = CrestlevelLevelWorld_m + 2/3 * H.
  3. If branch is not weir
  4. If branch = connector; calculate average width and average slope
  5. Calculate Depth_m.x ,WettedArea.x, WetterPerimeter.x, HydraulicRadius.x, Velocity.x
  6. Calculate Hslope, dH, Time
  7. HlevelWorld_m.y = HlevelWord_m.x + dH
  8. ylevelWorld_m.y = yLevelWorld,x + dH
  9. Calculate Depth_m.y ,WettedArea.y, Velocity.y, VelocityHead
  10. ylevelWorld_m.y= HLevelWorld_m.y – VelocityHead

Culvert and Rectangle Culvert

  • dH is a 3d vector. x = dH outflow, y dH friction, z dH inflow
  • dH x outflow based on carnot
  • dH y friction based on Chezy, with coeff = k (m)
  • dH z inflow based on contraction coefficient of 0,6, so xi = 0,44
  • If branch downstream = culvert, dH x = 0
  • If branch upstream = culvert dH z = 0
  • Extra info needed is type up-streams and down streams. local_type_up and local_type_down
  • Extra info needed is W and H up and down if type is culvert. local_WH_up and local_WH_down
  • Hlevel.x culvert = Hlevel.y type_down + dH.x
  • Hlevel.y culvert = Hlevel.x + dH.y. So dh.z is not added yet
  • Ylevel.x and Ylevel.y are based on Hlevel.x .y – velocityhead
  • dH.x and dH.z are based on the type of the adjacent branch.
  • dH.x and dH.z is not yet calculated with Rectangle Culvert.


Area pipe

Chezy coefficient
Chezy energy slope

Manning energy slope
Slope energy line
Sharp crest free flow
Partially filled pipes
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