If it is wrong

Symptom to cause, in order of likelihood.

It looks wrong

Symptom	Cause
Everything is flat grey	`SpecPanorama` is still the 4×4 placeholder, so the reflection is a uniform tint. Assign a real panorama
Everything is blown out white	`SpecularScalar` against an HDR panorama. It defaults to 0.12; go lower before going higher
Every surface is a mirror whatever the roughness	the panorama has no mip chain. Set mip generation to anything but `NoMipmaps` - roughness picks a mip, and the material compiles and renders fine without one, so nothing tells you
Everyone is pink	`SkinAmount` above 0 on a mesh with no vertex paint. Unpainted geometry arrives white, so the mask reads 1 everywhere. Paint red, or leave `SkinAmount` at 0
Metal everywhere	`CRM` blue is metallic. A pack with occlusion there needs `Metallic` at 0 and `bUseCRMTexture` off, or a repack
The whole surface glows	`bEmissive` is on over an albedo with no alpha channel, which samples as 1
Reflections are too sharp at high roughness	`MaxMip` is below the panorama's real mip count
A visible seam down one side of every reflection	the panorama's X address mode is not Wrap
The diffuse has no terminator	the `DiffuseFalloff` row has no knee in it, or the sun is pointing at the camera. Gradients

The rim

Symptom	Cause
No rim at all	`bFriendFoeRim` off, or `RimIntensity` at 0
Enemies are blue	`bEnemy` is a static switch, so ally and enemy are two instances. Setting it at runtime does nothing
The rim washes the whole body	the rim row's black plateau is too short. Push the first colour stop later
The rim is a sub-pixel line	the opposite - the plateau runs too late. Pull it earlier
Debug mode 5 shows red over the whole body	correct. Mode 5 is the raw mask before the gradient shapes it
The rim reads as a sticker, not as light	`RimUpBias` and `RimHeightBias` at 0. They are what make it describe the silhouette instead of outlining it

Gradients

Symptom	Cause
Edits do nothing	the instance's `Atlas` points at a different atlas than the one you are editing
A row reads as the wrong colour entirely	`Atlas` is pointing at the Gradient asset instead of its baked `T_` texture, or the row scalars do not match your atlas's order
A row looks like two rows blended	a `Row` scalar has a fractional value. They must be whole numbers
The rim cannot separate from a white wall	the atlas format is LDR, so the rim clamps at 1.0. Set it to HDR

Lighting

Symptom	Cause
Rotating the sun changes nothing	expected. Nothing reads a light actor. Fort → Sync Sun From Directional Light
The light comes from the wrong side	`SunDirection` points toward the light, so it is the negated forward vector. Sync Sun handles this
Characters ignore the level's lighting entirely	also expected, and the point. Areas are dialled with `Indirect`, not with lights
Characters look pasted onto a dark room	nothing wrote `Indirect` for that area. It is the one knob that ties a character to where they are standing, and it starts at 1 everywhere
A character is a chrome cutout in a dark corner	`SpecDarkenExponent` is at 1. Raise it

Build

Symptom	Cause
`Sampler type is Linear Color, should be Masks`	a texture whose compression does not match the sampler type on its parameter. Usually a CRM pack that is not `TC_Masks`
An include cannot be found	the runtime module registers `/MobFort` at `PostConfigInit`. If the plugin failed to compile there is no mapping and the error is an undeclared identifier, not a missing file
Verify reports a permutation with no shader map	on a cold derived data cache, run it again. If it persists, that permutation is failing to compile - open the master and switch it on by hand to see the error
The Fort menu is missing	Editor Preferences → Plugins → Mob Fort Editor → Show Toolbar Menu
A hand edit to a master vanished	Rebuild Materials empties and re-authors each graph. Edit `author_fort.py` or the `.ush`, not the graph