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Author Topic: stair problem  (Read 5225 times)

marke

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stair problem
« on: August 31, 2008, 10:11:14 am »

Hi, I have attached an input file in which I am having difficulty getting the stairs to work.  The simulation runs but the occupants will not use the stair.  Any help or advice would be appreciated.

Thanks

Mark
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Charlie Thornton

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Re: stair problem
« Reply #1 on: September 02, 2008, 10:40:59 am »

Because of the way we handle stairways, they can't have an edge shared by two floor areas.  They have to be touching floor on one side only.

I've attached a picture as an example: (example01.png)

In the attached image, the stairway base attaches to both A and B.  The "door" at the base of the stairway can only attach to one floor area.  Unfortunately, we don't have enough rules in place to prevent the situation from happening, so Pathfinder just picks one when it generates the connectivity information for the model.  If it picks area B, then the base of the stairway will look like a boundary to occupants in area A.  The fix is to delete the portion of B behind the stairway.  Alternately, you could delete B entirely.

A quick test to see if a room properly "connects" to the rest of the model is to right-click the room, then click Select Connected Components.  All of the floor, stairways, and doors that are "connected" to that room will be selected.

I've attached a picture of your model with the relevant section of room marked with "Delete Me".

(attached as: stairs.png)

- Charlie
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Charlie Thornton

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Re: stair problem
« Reply #2 on: September 11, 2008, 03:11:41 pm »

Did deleting that section of floor fix the problem?

- Charlie
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andrea

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Re: stair problem
« Reply #3 on: November 14, 2008, 04:40:00 am »

Hi,

regarding the stair problems, I have found some difficulties when I try to use the "one-point stair tool".
I have tried to simulate the "stairwell example", by the PathFinder Example Guide.

Adding the stairs using "one-point stair tool", I have created the second flight of stairs. Since the tread and the rise of that stairs was both irrational numbers, the upper stair edge and the landing enge do not overlap.

Then, the simulation results showed:

- the people on the upper floor don't evacuate because they have no exits (the only exit would be the stair, but there is a little space between the upper landing and the stair);

- due to the little space next to the upper stair edge, this was considered like a exit and, then, some people on the second floor evacuated not going down but going up.

Visually, I don't see the little space, since it is very very small; I have solved the problem b deleting the second flight of stairs and using the "two-points stair tool" to recreate it.

Where Did I make a mistake?
Is there a way to overlap the edges automatically, when I'm not sure that they overlap perfectly?

Thanks,

Andrea
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Richard O'Konski

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Re: stair problem
« Reply #4 on: November 14, 2008, 09:36:59 am »

You didn't do anything wrong.  We've found that the one-point stair tool is a little trickier to use than the two point because we have such a tight tolerance for determining whether a stair is touching a room.  Right now the edges of the stairs have to match very closely to the connecting room in the z coordinate. 

Because the z coordinate of your stair is an irrational number, the best way to accomplish this is to "select" the z location for your room.  To do this, make sure the edge of the stair you want to connect to is visible in the Perspective view.  Then select a room tool.  In the property panel for the tool there is a button next to the "Z Plane" field that says "Select."  If you click this button you can graphically choose any point in the Perspective view and the "Z Plane" will be extracted from the z coordinate of the selected point.  So go ahead and click the "Select" button and then click the top edge of the stair.  The Z Plane will now be filled in with the appropriate value, and the next drawn room should connect appropriately to the stair. 

To double-check that your new room is connected to the stair, you can right-click on the room or stair and select, "Select Connected Components."  All the rooms, stairs, and doors that touch the item will now be selected.

The next beta release will hopefully help with some of these stair issues.  We've added "handles" that let you edit geometry.  One of these handles is one that let's you easily connect existing stairs to a room if they do not already touch.
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Richard O'Konski
Thunderhead Engineering