How to Repair Broken Sketches and Features in Your 3D Model Without Starting From Scratch

In this video, we're going to learn how to fix a broken sketch or a broken feature in our model. So first things first, if you were to open your model,  let's go ahead and go to the Appearances tab, this Display Manager here,  go to Green, Low Gloss Plastic, right-click, Edit Appearance, and add one of the large beams and one of the small beams. This is something we forgot to do in the last video, but we want to make sure those are accounted for.

Once you've done that, go ahead and save and close out your model and simply follow along for this video. So sometimes you're going to be making your model and you're going to create mistakes that affect your Feature Manager and break the model in your Display Manager, and you'll have to fix that model. We're going to show you how to do that now.

So what we have here is a table that I've built, and it starts with the top, which I set dimensions at 60 inches by 48 inches. Then I created holes for the legs to move through,  and I set those at 56 inches by 44 inches. Then we have the legs themselves, which extrude all the way up to this top surface.

And then underneath the legs, we have some foot pads that are built off the bottom of the legs. Okay, let's break this model. So the first thing we're going to do is delete the legs and see how the Feature Tree updates.

So I'm going to right-click on that legs feature and hit Delete. It's telling us right away, by the way, if you're going to delete this feature, it's going to affect this sketch, Sketch 7, and this feature, foot pads. Do you want to continue, yes or no? Let's go ahead and continue and see what happens.

All right, as we can see, Sketch 7, which created the legs, and the legs themselves have both been deleted, and you can see that they're missing from our model. There are no errors showing in the Feature Manager because the model can still update just fine. It just doesn't happen to have any legs.

So I'm going to click Control Z, undo that action to bring those legs back. All right, next, let's delete the face that the foot pads are made from. Okay, first, I'm going to look to see what face that is.

All right, it's this corner right here. All right, I'm going to move this blue bar above the foot pads and delete the face that we use as the plane for the sketch, and then bring the bar back down and see what happens. Okay, so we've noticed that the face is gone.

That's because we added that Delete Face feature, and then our Feature Manager, we see yellow text, which tells us that there's an error in our model. If we open up that feature to look at the sketch, the sketch also has yellow text, which means there's error somewhere in the sketch. All right, so the first thing we want to do when we're fixing a sketch or a feature that has an error is we go into the sketch, and we right-click and go to Edit Sketch Plane.

The first thing we want to do is make sure there's a plane for the sketch to live on. In this case, it's missing that face because we deleted it. So I'll go ahead and right-click, delete that, and create a new plane, or rather assign a new plane for that sketch to live on.

All right, it's nice and blue. It's better. All right, let's go ahead and continue.

All right, we have a plane, but the sketch still has an error. So let's take a look at that. Let's open up the sketch, and we can see all of our entities are black except for this dot right here, which is yellow, and it's got a yellow reference.

That means it's a broken reference. With that face gone, that reference no longer exists. It can't recognize it.

So I'm going to delete that problematic reference,  and I'm going to create a new reference. There you go. It's black, and it's fixed.

Let's close it out and see what happened. All right, now the sketch got fixed, and so did the feature, which tells us that that issue was always embedded in the sketch, and it just happened to affect the feature. Great.

I'm going to go ahead and delete this face, or delete this command that says delete face,  because we no longer need it. All right, and then I'll save my work. Next, I'm going to delete the face that the legs extrude up to, in this case the top plane.

So I'm going to go above the legs,  go to delete face, all right, and then bring this bar back down to see how the model is updated. Okay. So not only is this top face gone, but our legs are gone completely, and there's some sort of issue with the foot pads.

This brings up the difference between yellow errors and red errors. A yellow error occurs when there's an error either in the sketch or the feature, but it's not stopping the feature from actually manifesting itself. The feature still has enough information to grow and exist.

A red error means that the error is so egregious, if you will, that the feature can no longer exist in your display manager. It's completely gone. It's kind of a more intense version of the error, right? So let's fix both.

Now, oftentimes, if you have an error in your feature manager, it's going to affect other commands that come later because things are referencing other things. So what you do in a situation like this is first bring this blue bar up by clicking it and dragging it just below the very first occurrence of the error,  and start fixing the errors in order one by one. All right.

So the first thing we're going to do,  just like before, open it up and see if there's a problem with the sketch. If there was an issue with the sketch plane or the sketch itself, we would see this either in red or yellow,  but it seems to be okay. So the problem is not with the sketch.

The problem is with the feature. So I'm going to right click and edit the feature and see what happened. Okay.

I see what happened. We did an up to surface extrusion, but the surface that once was there no longer exists. So there's nothing in this bar.

Therefore, there's nothing for those legs to extrude to. So why don't we switch that and just do a through all instead? Actually, better yet,  let's do up to vertex and click that corner. All right.

All right. We brought our legs back. Now,  let's roll this bar down to see how it affected our foot pads.

All right. There's still an issue with the foot pads. We'll look at the sketch first.

And of course, we want to look at the sketch plane. Sketch plane seems okay. So let's look at the sketch next.

We'll edit the sketch. And it looks like it's missing a reference. There we go.

Okay. It's a coincident reference that is no longer there. We're going to right click, delete it, and go ahead and just create a new coincident reference.

Instead, I'm actually going to create a vertical reference here and a horizontal reference between these two pieces. All right. It's fully defined in black.

All right. It's fixed. Now, even though this delete face still has removed the top face of our tabletop, we were able to fix the model so that all the other pieces can still manifest without any errors.

I'm going to go ahead and delete this face because we no longer need it. Looks like we got to fix it again. So let's go through and just create those legs real fast.

Allow me a moment to create these legs. All right. I will delete this.

Start a sketch on the bottom of that leg. Attach some feet. I'm going to highlight all four circles.

Make them equal to each other. Give them a dimension of two inches diameter. Close that out and extrude them by about a half inch.

Uncheck merge result. There we go. All right.

Now, the last thing we want to do is affect the legs by changing something in our early dimensions. So as you can recall,  the holes for our legs were set at 56 inches by 44 inches. I'm going to uncheck merge result here.

There we go. Now, say I decide that I want to shrink this table to 48 × 24. Let's go ahead and do that.

Let's see how it updates. So I'm going to go to the top and open up the sketch and make this, say, 48 inches and make this 24 inches. Okay.

Great. Oh, it's already telling us there's going to be an error. Let's go ahead and see what that is.

All right. It can't create a hole for this leg or for these four legs because there are no bodies for it to cut through. The hole dimensions are outside of the dimensions of the table.

So I'm going to fix the table dimensions first. Bring that back to 60 inches by 48 inches. All right.

Now, it's fixed itself. The holes for the legs and the legs are both brought back. Great.

But this is also telling me that I've got an issue in the design of my part. I set the hole dimensions as an independent piece of design reference as opposed to actually referencing it to the outer dimensions of the table itself. So let's fix that so our model can be a little bit more intelligent.

All right. Let's remove these dimensions because they're kind of arbitrary. What actually matters is that these holes and the legs themselves are equidistant from the ends and they are two inches from the sides and the top.

All right. Great. The model looks the same,  but let's go back and change the outer dimensions.

Let's go ahead and make this 48 again and make this 24. All right. Now, it's updated cleanly.

This just goes to show the importance of using references like coincident and concentric and collinear as often as you can in your model design so that when you make changes to your model, it'll update cleanly throughout the entire piece as opposed to causing a ton of broken errors in your feature manager,  which you'll then have to go back and fix. Thank you. That's it for this video.

In the next video,  we're going to do a quick review of how to navigate the graphics area with our model as well as set preferences so we can be confident moving forward in the course efficiently as a class.