> ## Documentation Index > Fetch the complete documentation index at: https://docs.rageon.dev/llms.txt > Use this file to discover all available pages before exploring further. # Portals and openings > Connect rooms, open the interior to the street, cut windows and holes, and set up mirrors. A portal is the opening that links two rooms, or a room and the street. The game draws the interior through portals, so every room must be reachable from the street through a chain of them. The walls open a hole where a portal sits, with no extra step. ## Connect two rooms **1. Draw two rooms that touch** Rooms drawn almost touching count as sharing a wall. Give them different names. **2. Click Portal** Click **Interior** (**1**), then **Portal** (**2**). Click on the wall the two rooms share, then click again further along the same wall. The opening is the stretch between the two clicks. **3. Check the direction** The new portal is selected. Its direction reads `… → …`, from one room to the other. Press **F** to flip it, or click **Flip direction** in the sheet. The opening is 2.2 m high, or the room height if that is lower, and at least 0.1 m wide. Hold **Ctrl** to skip snapping. If a click does nothing, it was not on a wall shared by two rooms. > [!WARNING] > > Direction matters. An inverted portal loads in game, and the interior disappears from one side of the door. ## Open the interior to the street Click **Entrance** (**3**) and click twice along an outer wall. The portal goes from the room to the street and is marked **Entrance**. A structure with rooms needs at least one Entrance. A portal to the street always runs from inside to outside, so **Flip direction** is disabled for it. A physical door is a prop attached to the portal: see [Props in structures](/projects/structures/props-in-structures.md). ## The Portal sheet Click the portal in the tree. The tree lists portals by an internal id, not a name. ![Portal sheet with direction Room to street, Entrance on, Width and Height, and closed Appearance and sound and Flags sections](https://mintcdn.com/rageon/_nzjx4zmIQAxf8Hl/images/structures/structures-portal-properties.webp?fit=max\&auto=format\&n=_nzjx4zmIQAxf8Hl\&q=85\&s=32d235b7aa7a1a5868babda26f25fbf3) An Entrance portal: Room to street, Entrance on, Width and Height. | Option | What it does | | - | - | | **Direction** and **Flip direction** | The two sides, inside to outside. Swaps them and reverses the corner order. | | **Entrance** | Marks the door the player enters through. The number of Entrances is what the game stores as the interior's exit portals. On for portals made with **Entrance**. | | **Width (m)**, **Height (m)** | Resize the opening and keep its center, base, and direction. At least 0.1. | | **opacity** | How much the portal lets you see through, 0 to 255. 0 is transparent, which is normal for a passage. | | **mirrorPriority** | Which mirror wins when two are in view. Counts only with **Mirror** on. | | **audioOcclusion** | How much the portal muffles sound through it. | | **Flags** | **One Way**, **Mirror**, **Water Surface**, and more. See [Flags](/projects/structures/flags.md). | Portals also have handles in the view: corners, left and right sides, height, and base. ## Mirrors A mirror is a portal with the **Mirror** flag on. Turn it on in **Flags**, and set **mirrorPriority** when two mirrors can be in view. The other **Mirror …** flags are described in [Flags](/projects/structures/flags.md). A room also has **Mirror Potentially Visible**. ## Openings and windows Click **Scissors** (**4**). Choose **Opening** in the bar and drag a rectangle over a wall, a floor, or a ceiling face. The hole appears as a row under the part. An opening with no portal is only a hole: the game draws the sky and fog through it. To make it a passage, select it and use the **Opening** sheet. | Option | What it does | | - | - | | **From** | The room the portal leaves from. Suggested by the wall the opening is in. | | **To** | The room on the other side, or **street**. **street** makes it an Entrance. | | **Set portal** | Turns the opening into a portal: same hole, now with direction and flags. Needs four corners and different **From** and **To**. | With several openings selected, **Set … portal(s)** converts those whose rooms could be guessed. Pick the rooms by hand for the rest. For a window that faces the street, use **Set portal**, then turn **Entrance** off. **Cut editable geometry** in the bar also cuts the structure's own geometry where the hole passes. See [Geometry](/projects/structures/geometry.md). ## Cut or split a room Switch the **Scissors** bar to **Plan**. Start an outline on a room, click its vertices, and press **Enter** to close it. The area inside the outline is removed from that room. Use at least three points, without crossing edges. **Backspace** removes the last point. If what remains falls into several pieces, the largest keeps the room's name, portals, and props. The others become new rooms named `… (2)`, `… (3)`, with no portals. Connect them with the **Portal** tool, or the Checker reports them as unreachable. ## Troubleshooting > **No Entrance: without a room portal to the limbo the player cannot enter.** > > Use **Entrance** on an outer wall. The limbo is the street. > **Nothing leads from the limbo to room "…" — it will not render.** > > The room cannot be reached from outside. Add portals that chain it to a room with an Entrance. > **Portal "…" leads to the limbo but its corners are in outside-to-inside order.** > > The portal to the street is inverted. Delete it and make it again with **Entrance**, clicking along the wall from inside. > **Portal "…" is marked as Entrance but does not go to the limbo.** > > Turn **Entrance** off, or point the portal to the street. > **Portal "…" leaves from and arrives at the same room.** > > Delete the portal and make it again between two different rooms. > **Portal "…" points to a room that does not exist (…).** > > The room was deleted. Delete the portal or recreate the room. > **The corners of portal "…" are not coplanar (… cm off the plane).** > > A corner was dragged off the plane. Make the portal again. > **Portal "…" has no area.** > > Resize it with **Width (m)** and **Height (m)**, or delete it. > **Portal "…" is … cm from the wall of room "…".** > > A warning: the portal is not on the wall. Move it onto the wall. > **The shell did not open the opening for portal "…": it does not fit entirely in a single wall.** > > The portal crosses a corner or overlaps another opening. Move it inside one wall. > **An opening in "…" faces the street but has no portal, so the game will not draw the outside through it. Select it and use Set portal; turn Entrance off if it is a window.** > > A warning. Select the opening and click **Set portal**. Turn **Entrance** off if it is a window. This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.