Hello Michael,

Got a free moment away from work and family this month. Back to my strat model project and the learning curve for NURBS modeling.

I'm trying to "rout" the region for the tremelo assembly. I built 3 solids and used them to try and "rout" the body.

Unfortunately, I have missing surface in the result. Pictures of the solids and the result below. Model attached.








I think it may be because I wasn't able to get the 3 solids to join successfully so I just used them to boolean diff the body.

I also tried to punch them through the top and bottom of the body, but it didn't seem to make a difference.

Any suggestion regarding the best way make this pocket? I guess my way didn't work too well.

Thanks as always.

Jeff

Have you tried merging the three solids without the filleted edges, boolean the result from from the main body THEN add the fillets?

I'm still coming to grips with MoI myself, but I've learned from other programs that it's often best to leave the fillets for last.

-GW

Jeff, I see that the one surface went missing whenever you Union welded the larger vertical block to the smaller one.

One way I found around that was to 1) use the top of the smaller block to project it's shape to the top of the larger one.


Then 2) Extrude that profile from the face of the larger shape to where the top of the smaller one used to be.


Then 3) Union weld the top extrusion to the bottom block.

It seems that the two blocks had a lot of space sharing issues, and a fight ensued. ...hope this works the same for you.

Hi Jeff, at first glance I was kind of confused because I did not see that 3 solid assembly anywhere visible in the model that you had attached.

Is that 3 solid assembly hidden with the name "trem rout" ?

Keep in mind that I'm not familiar with all the various labels and structure of your model so it's hard for me to know what things I'm supposed to hide and show in order to replicate your problem. If you can set things up in the model that you attach so that the pieces you are asking about are all visible and more obvious that would make it a lot easier to help!

One thing that I noticed was that in the stuff labeled "trem rout", there are not only some solids there but also some extra duplicated surfaces at the bottom of them, here I have slid the solids over to show them:



Is it possible that when you're doing the boolean you are selecting those extra surface pieces along with your solids? If so then that may be causing some difficulty.

Hmm, but also now that I fiddle with it a bit more, the boolean union seems to be having some difficulty figuring out this coincident overlapping area here:



Surfaces that overlap exactly on top of each other like that can sometimes be more difficult for the booleans to process, I'll take a closer look at what's going on there.

- Michael

Nice...



Yes... I think those two pieces didn't like existing in nearly the same space and time.
Also try Trimming the sections from the body separately in succession.

The other way you can do it is to do the boolean union and delete the bad faces (looks like they have messed up trimming boundaries somehow) and then contruct a new replacement face by selecting this edge down here and extruding it up:



Then join the extrusion to the other pieces to make a finished solid - that's what I did to get the unioned result in the attached 3DM file.

- Michael

Michael, I tried that, plus a Loft and a Network. There were even segments that I had to Merge (curves).

But for some reason, the new surface refused to Join to the existing structure.

Thanks everyone. I'm sorry I have so many "pieces" in my model. I'm trying to save everything in case I have to rebuild things. Which I've already done a few times. BTW, I didn't fillet the solids before routing.

Yes, trem rout is the stuff related to the routing of the trem pocket. I think I left the curves with the extrusion used to create the solids. I believe when you extrude from curves the curves are left behind.

I was going to try different paths to try and fix this, but I wanted to make I knew what was messing things up first. Looks like boolean diff got confused when I used the multiple solids. Also, merging via boolean union got confused because of the coincident surfaces. I thought boolean union liked it when you "bury" one solid into another. I guess this isn't the case when you share large regions of surfaces.

I'll try trimming and union and also the project and extrude methods to get some practice making the "routing" solid.

Thanks again!

Hi Mike,

> But for some reason, the new surface refused to Join to the existing structure.

You've got to remove the existing bad surfaces first - the area that looks like holes actually has some surfaces there, but they have a mangled trimming boundary so their display is messed up.

So to fix that you've got to do an Edit > Separate first to break the thing into individual surfaces, then do a window select (with the "inside only mode" - start in the upper left corner and drag to the right) to capture the bad faces and delete them. Then you'll have an actual open space there that can have something joined in.

Otherwise if you don't delete the bad ones the edges there are already joined between 2 surfaces and that's why they would not accept any new joins in there because if they did join in that would be trying to have edges shared by 3 surfaces instead of just 2 surfaces.

- Michael

I also tried repairing the body after doing the boolean diff, but that experience didn't go well.

Thanks Michael. That may explain the problems I had with trying to repair the solid and the body.

I forgot some of the things I tried since its been a while since I last had free time to work on this model.

Hope to someday build this thing on my Carvewright.

Hi Jeff,

> I also tried repairing the body after doing the boolean diff, but
> that experience didn't go well.

That was probably the same issue - the thing that looked like a hole was not quite exactly a regular open hole but actually a surface with a messed up trimming boundary. That needs to be removed so you really have a hole there that can then be patched up.

It's a bit of a tricky operation to select a messed up face like that since it doesn't have any of the regular shaded display to it to click on (that's a side effect of having a messed up trimming boundary - messed up trimming means messed up display meshing will happen as well) - instead you have to do a strategic window select around it to select it and then delete it.

- Michael

>You've got to remove the existing bad surfaces first -

Interesting, Michael.
I noticed something strange about those broken segments, a sign of something more off.

>I also tried repairing the body after doing the boolean diff, but that experience didn't go well.

I'm sure it's because the body inherited the existing messed up surfaces.

Also, this issue must also be akin to the instances when I perform a trim of some sort and end up with the random looking naked surface squares.

The easiest way to fix this is to draw a line straight across from a side view level with the top. Then move the smaller block so it sits exactly on top of the bigger one. Boolean union will then work. Then cut the top back to size with a boolean diff using the line you drew first. Delete the top solid.

Hi Mike,

> Also, this issue must also be akin to the instances
> when I perform a trim of some sort and end up with
> the random looking naked surface squares.

Yeah most likely those were also messed up trimming boundaries. Any kind of manglement in the trimming boundary will make for odd display mesh generation like that. That could be stuff like parts of the trimming boundary crossing over itself making a self-intersection.

- Michael

So in this case there appears to be a bug in the boolean handling where it's keeping the wrong surface piece.

This kind of ghost surface piece here:



When you turn on its surface control points, the control points for the actual surface are way up here:



So the trimming boundary is totally off of the surface - the trimming boundary itself is in the right spot for the boolean result but the boolean seems to have decided to keep the wrong surface piece as the underlying surface part of the face.

This is a simple enough case that I may have a good shot at tracking it down and fixing it, I'll give it a try in a bit.

- Michael

I resurfaced the 4 fillet corners of this object and the boolean succeeded. FYI