Solid Bodies Sharing Features & Patterns Issues.

[andrewdroth]

I ran into an issue with solid bodies that share features today. I've made a simplified version of the issue to share via a screen-cast below. 

If you have two or more bodies that share a cut feature, and you delete the defining feature of one of the bodies, there is no way to remove the association of the cut feature from that body. The body is in limbo, and can't not be removed without removing that cut feature. You can't un-select the body.

The other issue pertains to patterning a shared cut feature. If I define a cut feature in one body, and a different one in another, then use one pattern feature to pattern both cuts, I can end up getting the wrong cut showing up in the solid body. It seems to work properly is the distance is set to all, but not if there is a distance set.

[mcgyvr]

To your second one.. (haven't looked at the first yet..)

Notice which "solid" (shown in magenta) is selected as the one that should be effected by the extrusion..

When you change to a distance you need to select both solid bodies..

The pattern is set correctly to effect both solid bodies but the extrusion is not at that point..

[mcgyvr]

and can you please post the ipt files..

[mcgyvr]

and same issue for the first..

You aren't selecting the right solid bodies for these features to effect..

[andrewdroth]

For the first, I want the cut to affect both bodies, and it does. But when I delete the main (original) extrusion for one on the bodies, I can no longer un-select that body from the cut feature. I can't delete that body without deleting the cut.

In the second, the intent was for the cuts to only affect one body each, but to have both patterned using the same feature pattern. Notice that the initial cut doesn't show up, only the patterned ones. For instance, if you had a hole in one plate, and a slot in the other, but you want to pattern both with one feature. 

[Curtis_Waguespack]

Hi andrewdroth,

If the intents is as you say it is, I think you're just running into to the limitations of the history tree and multi-body parts, so you'll need to adapt your workflow.

For the first case, I don't understand the end goal of deleting the body, so I don't know what to suggest. But see the tip below***

For the second case, that means 2 patterns, with the spacing and count tied together so that pattern 2 uses the parameters of pattern 1. This way when you change pattern 1, pattern 2 updates as well. Or I might build the pattern using work axes, and then build the 2 patterns in the resulting part files. see the tip below***

***On modeling with multibodies:

I see too many folks try to build complex assemblies using the multi-body workflow. This results in a house of cards and/or with the user painted into a corner.

What often works better, it to work out the general interrelated fit using multi-body parts, then use the Make Components tool, then edit the resulting parts and add the other details to those parts at that level, often relying on shared parameters from the base multi-body part.

I hope this helps.
Best of luck to you in all of your Inventor pursuits,
Curtis
http://inventortrenches.blogspot.com

[andrewdroth]

This is the first time I've had the solid in limbo issue with my method of modeling. I had a shell plate with a lot of nozzles hole cut in it. The design changed to multiple shell plates, so I created those bodies, then modified the cuts features to affect those bodies. I then deleted the revolve feature that defined the original single shell body. But I hadn't realized the solid would stay. I should have removed it from the cut features, but I though it would be a mute point once the revolve was deleted. I continued working for a bit, then went to rename my solids before performing a Create Components. That's when I realized a had a rouge solid with no option of deletion.

For the pattern issue I think it would be handy to keep it as one pattern feature, and it does work as long as the cut extents are set to 'All'. It sure seems like a bug when the first instance isn't included in the pattern.