Installation

In Blender open Edit, Preferences, Get Extensions, then use Install from Disk and pick the reflection_light_placer zip.

Placing a light

1. Open the Light Master tab in the 3D viewport sidebar (N) and press Click to Place Light, or press Ctrl+Shift+L in the viewport, or use Shift+A, Light, Reflection Light.
2. Move the mouse over your object: the light follows so its reflection (Reflect mode), its light (Direct) or its rim (Rim) lands under the cursor. Use Rendered view to see it live.
3. Scroll for brightness, Shift+scroll for size, Ctrl+scroll for distance, Alt+scroll to roll, Ctrl+Shift+scroll for gobo sharpness. On a trackpad swipe two fingers up and down, or use the + and - keys with the same modifiers.
4. Tab or 1, 2, 3 switch Reflect, Direct and Rim. T switches Area, Spot and Point. The < and > keys step through gobos, H turns the gobo off, K and Shift+K make the light warmer or cooler, I solos it.
5. Click to keep the light, Shift+click to keep it and place another, right-click or Esc to cancel.

Editing

Select a placed light and a ring of controls appears around it in the viewport. Press a control and drag left/right or up/down to change brightness, temperature, color, size, distance, cone, gobo, reflection shape or reflections; Shift drags finely, Ctrl snaps, Esc or right-click cancels. Click a control for its exact fields. The Light control holds Light Type, Placement, Re-aim, Solo and Delete. Turn the ring off in the viewport Overlays menu (Light Master Controls). Moving a light by hand keeps it aimed at its target.

Surprise Me

Builds a new key, fill and rim lighting with a colour mood around the selected objects, or the object you lit last. Pressing it again replaces the previous surprise; lights you placed yourself stay.

Gobos

Drag the Mask control on the ring to step through patterns, or click it to pick a category and a pattern from the gallery. Sharpness moves the pattern card toward the subject for crisper shadows. Moving patterns play over the timeline; turn Animate off to hold one frame.