Drawing Truss Lacing - Trimming/Contouring Pipes

[Wesley Burrows]

If I were trying to model the side lacing on a truss.  How would I get the selected extrude along a path to trim it's ends contoured to the top and bottom extruded circles?  Or am I approaching this the wrong way?

 

 

I tried subtract solids,  but it doesn't remove the end,  I assume because the top and bottom pipe have a hole through them.   I'm sure I'm just being an idiot.   What is the smart way to do this?

 

[Pat Stanford]

If you really need to do it, you would do it more or less the same way you would build it.

 

If you are going to radius the end of the lacing, you would probably not also drill a hole in the top or bottom pipe. You would just trim the lacing and then weld them together.

 

In this case, just make a sacrificial solid extrusion the same diameter as the pipe without holes and use that to trim the lacing. Make sure the Retain Subtracting Object check box is unchecked unless you are going to use it to do other laces.

 

But perhaps a bigger question. Do you need to make this into a Solid at all?  If this is going to be part of a symbol, or even a group, could you just intersect an over length lacing and not worry about the extra solids operation?

 

Unless you are selling truss, or are going to do extreme closeups of the truss, it is unlikely that in any rendered view that a recipient of the drawing would ever know if the lacing is over length and just hidden by being inside the pipe.

 

I always recommend that people not spend time modeling things that won't matter. I worked with a client who insisted on putting hanging wires on the backs of picture frames because that is how they would actually be hung. But then he did not bother to put the frame at the fractional angle that would result in real life. So he was spending time end energy modeling something to make it "real" but that would never be noticed in a rendering.

 

Only you can know 

[Wesley Burrows]

14 minutes ago, Pat Stanford said:

If you really need to do it, you would do it more or less the same way you would build it.

 

If you are going to radius the end of the lacing, you would probably not also drill a hole in the top or bottom pipe. You would just trim the lacing and then weld them together.

 

In this case, just make a sacrificial solid extrusion the same diameter as the pipe without holes and use that to trim the lacing. Make sure the Retain Subtracting Object check box is unchecked unless you are going to use it to do other laces.

 

But perhaps a bigger question. Do you need to make this into a Solid at all?  If this is going to be part of a symbol, or even a group, could you just intersect an over length lacing and not worry about the extra solids operation?

 

Unless you are selling truss, or are going to do extreme closeups of the truss, it is unlikely that in any rendered view that a recipient of the drawing would ever know if the lacing is over length and just hidden by being inside the pipe.

 

I always recommend that people not spend time modeling things that won't matter. I worked with a client who insisted on putting hanging wires on the backs of picture frames because that is how they would actually be hung. But then he did not bother to put the frame at the fractional angle that would result in real life. So he was spending time end energy modeling something to make it "real" but that would never be noticed in a rendering.

 

Only you can know 

 

 

Thanks Pat!  I thought that might be the case.   Your points are all very valid.   More for my curiosity I guess and problem solving.  Though as you state,  for 99% of people's use cases, it's likely not a problem to really bother solving.

Edited November 12, 2017 by Wesley Burrows

[Phil hunt]

I guess you could have made a solid tube and then did a subtract solid and when you had completed all the operations pasted in place the origonal hollow tube.....I like adding solids and then putting a curve on the joint for really close up work....I thinks it’s a fillet in the 3D toolbox......

[AlanW]

Can also make an array with one section of truss.