The Origami Forum

Can someone help me with collapsing this part?

That is the only part I have troubles with....

That is because it cannot possibly be correct. There is a vertex in the center that leads to nothing...

So how could I collapse it then?

What kind of convention is that? The diagram has solid black lines, solid red lines, dashed red lines and solid gray lines.

The model was created by Robert J. Lang so the CP should be correct

Brimstone wrote:What kind of convention is that? The diagram has solid black lines, solid red lines, dashed
red lines and solid gray lines.

Black: mountain
Dashed Orange: valley
Grey: collapsing lines
Red: the basic CP lines of a box pleating model
Those colors are pretty common....

It's not that common to show possible choices of hinge creases instead of just choosing some. It is also not common using two different colours just for two conceptually different kinds of valley-folds. Anyway, since I'm on vacation, I might just fold these lines and shoot the collapse.

EDIT:
So I folded the small collapse. I think the easiest way to do this is focusing on the two triangles in the middle. It is immediately obvious that these two uncreased triangles must be pivots.


Here I've started collapsing the bottom part, always keeping the uncreased triangles in mind:


This might seem like a big step, but I've just collapsed the rest of the solid black and red lines at the top of pictures 1 and 2:


And finally, the dashed orange lines are just open sinks halving the width of the entire thing, and the grey lines are the hinge creases. These are gonna be where they make the flaps of this bit fit in:

There is actually a crease line missing. I'll do my best to explain, but if you don't understand i can draw a picture. Basically, there should be a crease line running up from the vertex near the center, where two red lines slope upwards to form a peak. The missing crease line is halfway in between the two paralell grey lines
Again, if you don't understand I can just draw a picture

Oh, and yeah, as Merlyn said, there will be a crease from the meeting point of the two triangles and up, as you will notice in the collapse - it will be the line at the top of the top flap.

Thank you everyone for your help. I thought exactly the same, just wanted to make sure

Brimstone wrote:What kind of convention is that? The diagram has solid black lines, solid red lines, dashed red lines and solid gray lines.

CPs often get too cluttered and hard to decipher if you use the usual mountain and valley folds. That's the reason why often times people will use solid lines instead of mountain folds when drawing CPs. The colour helps to distinguish the lines further. I think there is no consistent set of rules what colours to use, so most of the colours might just be chosen randomly with a good contrast. Not so random is the colour of the grey hinge creases. These as well as the red solid lines change direction as often as they touch another crease. The difference between the two is however, that the red lines need to be precreased, as they are an integral part of the crease pattern. The grey hinges on the other side form as you collapse and many CPs will even omit them at all. It is nice though to have them as a reference but given that they will automatically form anyway, it can be easier to just leave them away when drawing the CP. If someone draws them, their unimportance is often reflected by a light grey colour.