generic subassemblies

[CADmgrMike]

Why can't Autodesk make the generic link subassemblies work all the same? I spent half a day trying to figure out LinkOffsetAndSlope subassembly only to find out the offset value is base on the assembly centerline and not the subassembly insertion point. What the??? The other link offsets work from the insertion point like they should.

Cmon Autodesk!!

[sboon]

Autodesk uses offset to describe a distance from centerline, and width for a distance from the attachment point.  As far as I know they have always done this in every sub that they created. Perhaps your designs are all based on fixed widths, but I certainly appreciate having both types of subassembly.

[CADmgrMike]

I understand now how it works, but IMHO they're not consistent.

The "LinkSlopAndVerticalDeflection is based on the insertion point of the sub, not the center of a baseline.

Also the help "picture" for "LinkOffsetAndSlope" implies the same thing.

It doesn't even show the center of the assembly or baseline that it is tied to. It seems confusing to me that if I want a (x)' offset from my EOP for a simple shoulder, I also need to know how wide the lane is to get that offset. What if my lane is targeted to something so that it varies in width. Then my offset width would vary because it's tied to the center line and not to the EOP.

Maybe it's just me.

[tcorey · Accepted solution]

Hi Mike,

I think you are missing the point. Autodesk supplies subassemblies that use Offset and others that use Width. There are probably infinite design conditions out there. Having both types of SubAssy helps you solve more conditions.

For the condition you describe, you should use LinkWidthandSlope. That will let you specify an offset from your EOP.

As the previous poster explained, if it says "Offset" in the subassembly name, it means offset from the corridor baseline. There are many design conditions that this function serves.

You mention LinkSlopeAndVerticalDeflection references the subassy insertion point. That is expected behavior. You don't see the word Offset in the title.

Best regards,

Tim

[CADmgrMike]

Ok, I stand corrected.

LinkWidthAndSlope did what I wanted.

Thanks for the help,

[troma]

Bumping this thread because it frustrates me too.  I understand the answer, and yes, it works.  But here is my bug bear:

When I'm putting an assembly together, and I add a LinkOffsetAndSlope, I know that I'm dealing with an offset from the baseline.  Say I accept the default 10m.  It doesn't look like 10m from baseline.  It doesn't measure 10m from baseline; no it measures 10m from the insertion point.  So if I have a 3m lane and a 0.5m curb, the link is drawn at 10m from there, i.e. 13.5m from the baseline.  However the corridor will build it as being 10m from baseline, i.e. 6.5m from the insertion point.  That is the unacceptable inconcistancy.  If it is going to be 10m from baseline, draw it so.

[tcorey]

What you see when you're creating an assembly is considered Layout Mode. The subassembly uses the Offset to Baseline as a width because it doesn't yet know where it's baseline is (even though it should know the baseline because the Assembly marker is there and wouldn't it cue on that?.) Once you create the corridor the offset will respect the baseline.

If the subassy offset is going to be controlled by a widening, you can somewhat work around the layout mode width by changing it to any number that makes your assembly look more realistic to you. When you run it, you're going to attach widenings, so the value you use here doesn't matter.

[troma]

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@tcorey wrote:

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it should know the baseline because the Assembly marker is there and wouldn't it cue on that?

...

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That's the point, Tim.

I just noticed another inconsistancy between the Offset and Width variety.  Working on the left of the assembly (a negative offset or width) the slope is opposite.  To go up at 2% with the Offset, you type 2%, but to go up at 2% with the Width, you need to type -2%.  How do I know that's for real and not just a layout mode thing to confuse me again?  Maybe it actually will go down at 2%, but it just looks like up in layout mode?

[tcorey]

That's because LinkOffsetAndSlope does not include a Side parameter. It uses a negative offset to determine the side. The LinkWidthAndSlope subassy does have a Side parameter so you don't need to use a negative width to go left.

Tim

[troma]

Ok, good point.