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# Bridge Modelling

#### nkpham

##### New member
Hi everyone,

I was wondering if anyone can help me out with my design problem. I'm new to using Pro E and am having trouble finding the proper functions to use. Here's my problem:

I need to create a bridge using a sweeps for both the horizontal and vertical directions. I can do one or the other, but I don't know how to combine them. Can anyone help me? Any advice will be most welcome.

Do you have a sketch or something to help explain it.

If you want to combine two sweeps you will need to merge them, but I dont think thats what you are after.

Mike

I have to model a bridge that has many curves horizontally. Since it is built on land, it has elevation changes also. From the tutorials that I have finished, they only teach how to make simple sweeps in one plane, i.e. I can either create the sweep that represents the horizontal changes or the elevation changes. I wanted to know if I could create more than one trajectory for the cross-section to follow. The only other way I know how to do this is divide the bridge into many smaller pieces, create the sweeps for the separate pieces, then blend the junctions (which would take a very long time). Does anyone know any other way? I saw the function in the advanced menu called var sec swp and was wondering if that was my answer. If it is, could someone tell me how to use it?

I have to model a bridge that has many curves horizontally. Since it is built on land, it has elevation changes also. From the tutorials that I have finished, they only teach how to make simple sweeps in one plane, i.e. I can either create the sweep that represents the horizontal changes or the elevation changes. I wanted to know if I could create more than one trajectory for the cross-section to follow. The only other way I know how to do this is divide the bridge into many smaller pieces, create the sweeps for the separate pieces, then blend the junctions (which would take a very long time). Does anyone know any other way? I saw the function in the advanced menu called var sec swp and was wondering if that was my answer. If it is, could someone tell me how to use it?

a var sec sweep will let you use more than one trajectory.

Make sure that the first traj you pick is the longest one.

You can probably just use pivot direction and select a plane that is parallel to your curves.

The cross hairs indicate the starting points on each curve so constrain the ends of your sketch to them and go.

Mike

I may have missed your intent but? If your bridge is defined by a coordinate system (elevation (Z), X, Y) can you create coordinate offset datum points per that data, create a datum curve through those points and use that as your main trajectory? Is Ver Sec Sweep the command that uses a second trajectory to define the ?normal? direction of the section?

What is a pivot direction.

Var Sec Sweep allows you to create multiple trajectories that control either the shape or direction of your object.

I was wondering whether there are any restrictions on this function. I followed your advice Miked and made sure to constrain my curves. For some parts, I received error messages I could not resolve. Is there only a certain amount of places where I can place my origin trajectory? As long as I create a straight trajectory, my object comes out fine. When I add curves to the first trajectory, I get error messages. Anyone have any answers for me?

create the profile using 2 projection so that u can have inclinations in any direction. or create 2 surfaces showing the vertical and horizontal inclinatipons. and project a curve on it. use swept blend to obtain the required bridge.

Variable Section Sweep (VSS):

Can use any no. of trajectories but only one section. The plane perpendicular to the ORIGINAL trajectory is the plane on which you are going to draw the section. Therefore, all your trajectories MUST pass through this plane. Otherwise you cannot draw the section itself. The section should be aligned to all the trajectories. The sweep stops even if one of the trajectories stops. So for the sweep to happen all the trajectories should pass through.

Sweep Options:

1. NrmToOriginTraj: Here the first trajectory is the original trajectory. The sweep is perpendicular to the original trajectory at the start and end.

2. Pivot Dir: Same as 1 but the sweep is perpendicular to the seclected plane at the starting and ending portion. (Only one plane can be chosen.)

3. Norm To Traj: Same as option 1 but the original trajectory will be the SECOND trajectory chosen instead of the first.

Suggestion: It is complicated to perform this operation in a single shot. It is better to draw all the trajectories as datum curves and use select trajectory option from VSS and draw only the required section. It is advisable to draw a trajectory in the centre of the sweep and select this as the original trajectory-not a must.