Custom Tunnel Portals

By default, when you mark a track or section of tracks and change the mode to “Tunnel”, SCARM will show single tunnel portals in the both ends of the selection if they are connected to other simple tracks. Read this if you want to override the default portals and change their look in the 3D viewer and download the sample file form the links below.

To create a custom tunnel portal, you can use the figures in SCARM. You can make it to look differently by changing the shape and colors or to create a double tunnel portal by tweaking two parallel single portals.

Before you begin, take a look on How to work with figures FAQ topic in the documentation, if you were not familiar with them.

1. Custom tunnel portals

Lets start with the following sample oval, which has a section in tunnel.

If you want to make custom tunnel portals in your track route, you will first need to remove the default portals. There is no such option in SCARM, but you can force the program to hide the portals while keeping the terrain shape with a small trick. Do the following:

1. Activate the Track heights by use of “View” > “Show Track Heights” menu.
2. Select the normal track after which the tunnel starts and alter the height at the tunnel portal to be a little different (i.e. 1mm / 0.04″ higher) while holding Ctrl key down.
3. This will disconnect the tracks as the heights at the join where tunnel starts are not equal. SCARM will not be able to make a join and will not draw the default portals.
4. Repeat steps 2 and 3 again for the other end of the tunnel.

The sample plan will now look like the one below.

Now you can make a simple portals, using several rectangle figures for the sides, the top and a black rectangle for the dark inside the tunnel. Here is just one example of a custom build portal.

Using this technique, you can make single and double custom tunnel portals with any shape and color, but limited to the functionality of the currently available figures in SCARM. Get the sample file form the links below and ungroup the portal to see how it is assembled from the different rectangles in the group.

You can also make a custom portal where SCARM does not place a default one, i.e. between the last normal track and the first turnout in a tunnel.

2. Double tunnel portals

If you have a double track route and want to make a tunnel with one double portal instead of two single portals, you can create a wider custom portal as explained above or use another small trick to modify and unify the single portals. The only requirement is the two single portals to be symmetric to the center between the two tracks like below.

To make one double portal from two single portals in 3D, we will “mask” the inner sides of the two tunnels with a black rectangle figure between the tracks, raised to the top of the dark parts and this will give an illusion for a single wide entrance. Do the following:

1. Create a Rectangle figure in front of the portals.
2. Position and rotate it to be in the center between the tracks so the short sides of the rectangle to overlap the inner rails.
3. Adjust the Properties so the “Vertical position” to match the height of the tracks and “Height” to be a little bit smaller than the tracks gauge multiplied by 4 (may need several tries for optimal look).
4. Set the color to Black or to very dark gray shade near black. This should be found experimentally in order to match to the color of the dark part in the default tunnel portals, which may slightly vary depending of the portal’s rotation angle.
5. See the result in 3D and repeat the steps from 2 to 4 in order to find the optimal coverage and look (may need several attempts). Reshape the rectangle using the control points and readjust its properties if needed.

When ready, the result should be similar to the images below. The red arrows are showing the black masking rectangles.

You can also use a second rectangle in order to unify the upper parts of the two default single portals with the same sequence.

Get the two samples from the links below to practice and experiment with them.

Sample projects

See also
How to work with the figures in SCARM

5 thoughts on “Custom Tunnel Portals

  1. I appreciate your “custom” tips from the blog. I don’t like to do things that disconnect the tracks from a line as it makes it difficult to “select all’ or large sections of that line. (i.e.., color a track to indicate a power division, or disconnect an area, put in smaller pieces to make a tunnel start/end look good in 3D)
    I wait until the track design for the build is complete before I focus on making the 3D elements look good. I save the track layout plan for build and the 3D version for visual presentation as separate (differently named) files.
    Thank you for the great software. I find it very accurate and like working with it!

  2. Fantastic programm, but where can I find the solution how to remove portals/tunnels.
    If it is possible to place them, it should be also possible to remove them again,right?
    But I cannot find the solution…….

  3. Hello Ron,

    If it is about how to go back from “tunnel” to “normal” mode of the track, just select the tunnel tracks and then press Tunnel button once or twice to toggle off tunnel mode.

    If it is about how to remove the default portals, that is described in the article above.

    If it is about how to remove the custom portals, select all the figures that form the custom portal and delete them (using Del key). To restore the tracks connection, you will need to equalize the track heights at both track ends where the default portal should appear.

  4. Scarm isn ‘t generating mountains with the tunnels and bridges anymore, how can I solve this?

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