Creating a Bidirectional Stair Sketch Pattern and Custom Top Steps with Global Variables in CAD

In this video, we're going to make a complex sketch pattern that moves in two directions. We're also going to make the top two stairs. So, first things first, let's go ahead and make sure that our heights sketch is visible.

That'll be our reference sketch we use to create the stairs. And let's go ahead and get our pattern ready. Let's create a sketch on this surface of this beam,  and let's create our first stair using the corner rectangle tool.

Grab that inside nested vertex. That's where that first stair will live. Let's go for a thickness of our standard board thickness.

And for the depth of the stair, or in other words, the run of the stair,  I want to create a brand new global variable for that. So, let's close and save the sketch. Go to tools, equations, and in this line that says add global variable, we'll give it a name.

We'll call it stair run. And let's assign it 6.75. Let's say we were able to source board that width. Great.

It created a global variable. We know that because it populated the cell and the evaluates to column. Let's close it out.

Save your work. Next, let's go ahead and reopen the sketch. You can just click on the sketch itself and select edit sketch.

Go to smart dimension. Grab that line and let's assign it our brand new global variable of stair run. Great.

So, this will be the instance that we use to create a pattern that both runs out and runs down. So, let's do that now. We'll go to linear sketch pattern.

First,  go to entities to pattern and grab all four lines. In the X axis that will run out,  let's make sure it's moving the right direction. Okay.

And let's set a distance to make it really easy to view. We'll call it like 6. Actually, let's make it a little bit more so we can see some space. Beautiful.

Now, we need to decide how many stairs we're going to create. Well, we've got 12 lines here, but the 12th step is actually the second floor,  which is already made. So, we need to make 11 stairs.

So, let's set our number of instances to 11. Now, let's go down to the Y axis and set that number of instances to 11. Let's give it some space so we know we're patterning in the right direction.

Once you know it, we're patterning in the opposite direction. We can fix that by clicking this button here. Great.

Now, we have all the instances that make up this pattern,  but we only want to keep the ones that represent our stairs. For right now, let's go ahead and click the green check mark, close out and save the sketch, and save our work. All right.

Let's go back and edit that sketch. So, highlight the sketch, click edit sketch,  and then select one of these new pattern entities, say this line right here. We'll see that it has an existing relationship of pattern to zero.

If you right click that, you can select edit pattern. All right. Now, for this, we need to go to the very bottom to instances to skip,  highlight that box, and you can see that it populated every instance with a pink dot.

The pink dot represents an instance that will be manifested. If we click on a pink dot, it becomes orange. It also populates this instance to skip box, and we have removed this instance from our final pattern.

So, we'll have to go through and click every pink dot that represents a stair step that we don't want to be there. For this column, keep the top stair, leave that pink,  and make everything underneath it orange by clicking the pink dots. All right.

And then this one as well. Beautiful. For right now, let's close out the sketch and see how that updated.

All right. You can see it kept this instance and removed all the rest. Let's close and save the sketch.

We're going to remove all the unnecessary instances,  so let's make our lives a little bit easier by hiding anything that we don't need. Let's click this eyeball tool. Let's go to our solid bodies, highlight the top one,  hold shift, highlight the bottom one, hide them all, and then we'll go back down to our sketch,  edit sketch, highlight one of these pattern entities, right click on pattern, click edit pattern, go to instances to skip, highlight the box.

Now go through and eliminate any stair that doesn't need to be there. We don't need this top one, but we do need the second one. So,  we'll eliminate all the stairs underneath it.

We're turning all of the pink dots orange. Okay. Great.

For the next one, we'll eliminate the top two, but keep the third. Keep the third and eliminate all the steps that occur below it. All right.

Note to editor, this may be a point in the video where we want to start speeding it up,  because it's going to be a lot of the same stuff. All right. We're on the fourth row.

Eliminate everything above the fourth step and everything below the fourth step. Boom, boom. We're checking our work.

So far, so good. Fifth row. I'm sorry.

Fifth column. Eliminate everything above the fifth step and everything below the fifth step. Okay.

Sixth column. Keep six, keep seven. Eliminate everything above the seventh step,  everything below the seventh step.

Seventh column. Let's check our work. Diagonal, diagonal,  diagonal, diagonal, diagonal, diagonal, diagonal, diagonal, diagonal.

Okay. We'll keep this one. Eliminate everything above it.

Keep the bottom step. Eliminate every stair step above that. All right.

Once you've done that, you can double check your work by looking at the top stair step here and tracing a diagonal line, making sure that a pink dot represents every stair that you cross. If you're happy with that, go ahead and close it out with this green check. All right.

Let's go ahead and close and save the sketch and save your work. All right. Now,  there are a couple instances that I did not eliminate.

I'm going to go back and edit those now. The pattern instances to skip. We'll remove this one and this one.

Beautiful. Now, while I'm still in this sketch pattern, I need to set the height and the distance of these stairs. So, let's first set the height.

This is our bottom step or represents the top of our bottom step. Let's grab that line and grab this line from the top of the actual bottom step. Make them collinear.

Now, we need to decide how far out these stairs travel. Here we go. What I want to do is I want them to overlap by the what equals to be one board thickness.

So, I'm going to get an overlap going, click this line, click this line, and set that to the board thickness. We'll find out in later videos why that is. All right.

Now, your stairs should be fully complete and black, fully defined. Close out your sketch. Save your work.

Wonderful. Now that we've done that, let's create the top two stairs as they will both be unique in their own way. Let's go ahead and bring back all of our solid bodies.

We don't need to hide them anymore. All right. Let's make sure that the ground plane is visible.

And let's start a sketch on that same surface of that beam right there. Let's go to convert entities and convert just the lines that make up the top two stairs. Make sure not to click any other lines you don't intend to select.

Here we go. If you can't find the line you're looking for, you can right click where it should be and click select other. And then of these choices, select the one that corresponds to the line you want to select.

Click the green check mark. All right. We have successfully converted those entities.

Let's extrude that. And in this case, we'll extrude up to this line from our ground plane sketch. Make sure that up to vertex is checked and select that line.

Uncheck merge results. Click the green check mark. Save your work.

Now I first want to cut some notches into this board. So I'm going to highlight a sketch on the board surface. Start a sketch.

Convert the entities of that board. Let's highlight all those entities. Select for construction.

And then let's create some rectangles that are going to be the notches that we cut out of that board. Let's go ahead and make sure all the rectangles are squares and that they are equal to each other. We of course do that by selecting a line that corresponds to the height and width of each square and making them equal.

And let's set that to the board thickness. And then we'll just go ahead and run a cut through that board. Make sure the cut is moving in the correct direction.

And then let's pattern, or I'm sorry, let's cut up to vertex and we'll select maybe that corner of that board. And we'll go ahead and close out the sketch. Save your work.

For this top stair, let's just put notches in the front. So let's go ahead and highlight that. And we probably don't need to convert entities here.

Let's just go ahead and make those notches. I'll start by creating a rectangle here. Let's turn that rectangle into a square by making the height and width equal to each other.

And then for this, let's grab a center line, find the midpoint of that board. And why don't we use mirror entities to mirror that notch? We'll go ahead and highlight that square, mirror about this line. It's still blue.

So let's give it a dimension equals board thickness. All right. Close with a green check mark, go to features,  extruded cut, and then up to vertex.

We'll just do the corner of that board and close it out. Let's go ahead and save your work. We can click this eyeball so we can just see the solid bodies.

We've created two unique solid bodies. So let's go ahead and make them green. All right.

Save. And that's it for this video. In the next video, we're going to set the rail pattern for the handrail.

And we're going to also learn how to use boss extrude off of a surface to set the height of that rail so that it's appropriate for children to use.