A four-vector parameter drives Base Color, white to start and later a pale blue. Specular is set to 1.0, Roughness to 0.1 and Metallic to 0.0 for now, so the surface can first be shaped to read as snow-dusted ice.

Roughness comes from the engine’s high-frequency noise texture. Only its red channel carries data, so R alone feeds Roughness (white is rough, black is smooth), multiplied by a Roughness scalar for overall control.

TexCoord × UV Scale feeds the texture’s UVs: a higher scale tiles more and makes the pattern smaller. At a UV Scale of 50 in the material instance, the texture becomes a barely-there surface detail. A texture is also cheaper than a procedural noise node, which is a long chain of instructions.

To track down jagged shadows, the first test is raising the directional light’s Shadow Resolution Scale. If that helps, the shadow map is the cause; if not, check polygon count, silhouette, normals, topology and shadow bias.

Shading Model is set to Subsurface, and Subsurface Color is promoted to a parameter with a brighter blue. Strongly contrasting Base and Subsurface colors in the instance make the lit and shadowed areas easy to read.

The jagged shading was fixed with the SSS opacity (Opacity Override, promoted to a parameter, set to 1 and then lowered). The sphere on the right uses denser geometry from Modeling Mode, so it shades more smoothly under the light.

Fresnel builds a mask from the angle between the camera’s view direction and the surface normal: low where the surface faces the camera, high at grazing angles along the edges.

ExponentIn sets the falloff (higher gives a thinner, sharper edge; 5.0 here), and BaseReflectFractionIn how much remains facing the camera (about 0.03–0.04). Fresnel × emissive_intensity × emissive_tint drives Emissive Color for an adjustable edge glow, all exposed in the material instance.

Parameters are grouped for the material instance: base_control (metallic, specular, SSS opacity, UV scale, roughness), sss (subsurface color) and Fresnel (ExponentIn, BaseReflectFractionIn, emissive_intensity, emissive_tint), then tuned until the surface shows clear shadow, mid-tone and highlight separation.

The same Fresnel mask also drives a Lerp between basecolor and basecolor2, pushed toward cyan in the instance, so the color shifts smoothly from face to edge. One Fresnel, two branches: base color blending and emissive edge glow.

Blend Mode changes from Opaque to TranslucentGreyTransmittance so light can pass through, and Refraction Method is set to Index of Refraction so it bends. Translucency decides whether light gets through; IOR decides how it bends. Lighting Mode is Surface TranslucencyVolume.

Fresnel masks the IOR through a Lerp (IOR 2 on the B input), which gives the look of a solid glass sphere.

Translucency costs more than Fresnel because of extra blending, sorting, lighting and overdraw. Where true transparency isn’t needed, Fresnel can fake glass-like edges more cheaply; the two complement each other rather than replace each other.

World Position Offset moves the mesh’s vertices in world space from inside the material. With Blend Mode back on Opaque and Shading Model on Default Lit, VertexNormalWS gives each part of the surface its own direction.

Used directly it reads every normal on the sphere and looks noisy. A MaskComponent node keeps only the B channel (up and down), and multiplying by −1 flips it, giving a clean top/bottom mask that pushes the vertices into icicle shapes.

The name comes from the physicist Augustin-Jean Fresnel. On set, a Fresnel lens shapes a light between spot and flood; in CG, the Fresnel effect is how reflection grows at grazing angles. The same optics, two applications.

It starts at the Codex download page. In Windows PowerShell, codex isn’t recognized yet, and the install script stops with an error. PowerShell 7 (7.6.6, which winget shows is already installed) runs the same script cleanly: Codex CLI 0.155.1 installs and opens in the terminal.

In the editor, the Unreal MCP plugin (Epic Games, marked experimental) is switched on, which needs a restart. Afterwards the editor warns that the Asset Manager has no entry for GameFeatureData assets, which game feature plugins need, so that entry is added to Primary Asset Types to Scan.

In the Model Context Protocol settings the server sits at /mcp on port 8000, set to start automatically, with tool search on. From the editor console, ModelContextProtocol.StartServer 8000 starts the server and ModelContextProtocol.GenerateClientConfig Codex writes a Codex config file into the project folder.

Started in the project folder, /mcp shows unreal-mcp as connected with 3 tools. The first prompt is read-only: which actor is selected, without modifying anything. Codex asks for approval before each tool call, then calls GetSelectedActors and get_label and answers DirectionalLight.

Two small changes that are easy to check: move MCP_TestCube to X 300, Y 0, Z 100 and read the transform back, then delete the cube and confirm it’s gone. The scene has its own level, L_Chess_Main.

Longer instructions, including explicit rules about what not to change, are written ahead of time and pasted in as one prompt. The first builds the board: 64 ChessTile actors labeled A1 to H8 on a 100 cm grid, checked for count, unique labels and transforms, with no materials, pieces or gameplay yet (2 min 27 s).

Before making any materials, a read-only pass maps what the material tools can do: create materials, add and connect nodes, set Base Color, Roughness, Metallic and Normal, make material instances, and assign them through a mesh’s overrideMaterials.

Next comes M_Marble_Master, built from two scales of procedural noise with softened veins and no texture images, exposing BaseColor, VeinColor, Roughness, VeinScale and VeinStrength, plus two instances of it. Codex recompiles the master and checks its 30 graph connections before anything touches the tiles (5 min 23 s).

Then MI_Marble_Dark and MI_Marble_Light go onto all 64 tiles, 32 of each, alternating like a real board and verified tile by tile (4 min 34 s).

The pieces are placed and named by color, type and square, such as White_Pawn_H2 and Black_Pawn_H7, with the tiles, board materials, lighting and camera left as they were (9 min 59 s).

/status after the pieces: about 10% of the five-hour limit left. The session then ends with exit.

The node chain is Stripe + Disc → Blend → Blur HQ Grayscale. Stripe generates the stripes, Disc sets the round area, Blend combines the two, and Blur HQ Grayscale softens the edges.

The result is exported as a PNG.

The PNG is imported into Unreal Engine and a new material is created. Its Material Domain is switched from Surface to Light Function, the texture goes into a Texture Sample node, and Texture Sample RGB connects to Emissive Color. Then the material is saved.

Back in the level, a Spot Light is added and the new material is picked as its Light Function Material. The black-and-white mask is projected through the light and controls the bright and dark areas inside it, for a striped projection like light through blinds, a fence or a gobo.

A Light Function material may not preview correctly: the pattern can be missing from both the material preview sphere and the Texture Sample node. This doesn’t affect the actual light.

Edward Hopper’s Nighthawks: a lit interior seen from outside through a wall of glass.

Gray-box layout of the shop: the gear-shaped counter and stools, the wall of gears and the shelves.

The gear models come from a free asset pack.

Kitty and Walter go to see a Chinese opera, where they meet the Townsend couple. Charlie flirts with Kitty while they watch the performance.

Dr. Fane and the Colonel go to the warlord’s quadrangle to negotiate, asking him to let his soldiers go to Mei-tan-fu to help.