Making and improvement of pop-up card

2021-03-20

I made a pop-up card after a long time. 
This model is the Ronvijoypur Mosque, one of the mosques included in the Bangladesh World Heritage Site “Historic Mosque City of Bagerhat".

Today, I will write about how to make pop-up cards and how to improve it, not about cultural properties.
In the photo, two almost the same cards are lined up, the one on the right is the first made. The modified version is on the left.
There were parts that did not go as expected, so I write down what was the problem and how it improved.

About the real mosque that became the model. 
At first I did a Google image search for “Ronvijoypur Mosque" and thought I’d put that link on my blog. But there were few images and other mosques with a similar shape is also on it.  So I drew it myself with reference to the photos and drawings so that the viewer would not be confused.

The mosque is made of brick and has a dome in the center.
The feature is that the four corners are cylindrical and the eaves line is a gentle curve (convex curve). This shape seems to be a characteristic of architecture in the Bengal region (around the 15th century).

The cylindrical towers at the four corners has the bulge lines like a string wrapped around. I’m not familiar with architectural terms, so I don’t know what to call it. 

The small gray U-shaped one near the roof, by the tower, is probably a rain gutter because it protrudes outward.

This was the first thing I made.  The dome was represented in steps, as I always do.

Points intended at the time of design

(1) The bulge of the eaves and roof. The folding position was slightly shifted to raise the center.

(2) The line below the roof is a eave slightly protruding, but this time they are cut out as a dotted line.

(3) I thought  the convex of the cylindrical part can be made as the line of the photo. But if it makes such a protrusion to a place that is only 2 mm wide, the paper may be torn. So I made only on the outermost side.

And I made a rain gutter. It sticks out a little from the roof.

With these things in mind, I designed the paper pattern and make a card.

After folding, I took photos as usual. When I was lighting from the back (as in the photo above), I thought it was complete.

However, when I lit it from the front, I noticed a problem.

Problem (1). The crease on the wall. Originally, it should be folded neatly along the red line (at roof) in the photo, but because the eaves are cut out in a dotted line, the yellow line part has an unintended crease. It can’t be folded neatly with the red line. If it was opened and closed several times, the yellow line will be strained, and the shape will be more distorted.

Problem (2). The place marked (4) in the photo is unstable because it is connected only at the top and bottom.

I took a picture of the bent state intentionally. This is an exaggeration, but it is easy to shift sideways, so I would like to increase the part that connects to the main body of the building.

So I decided to fix these and make the card again.

The cut line was erased so that the cylindrical part and the roof are connected.
The cutout of the eaves were made smaller to make it harder to break. I was still worried, so added a notch to the red line so that the roof and dome can bend smoothly.

Here is the result of the correction. This time there seems to be no unintended creases.

At the end, please check the movement in the video.

The world heritage “Historic Mosque City of Bagerhat" include other mosque. For example,  a mosque with nine domes,  and a mosque with 60 (more) domes. After making these pop-up cards, I will update the main site.

I will publish the pattern of this Ronvijoypur mosque, so please take a look at the pattern. 

(Translated : 2021.02.21)