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- Creating geometric relationships between entities in a design
- Adding variables and expressions to dimensional constraints
- Importing and exporting PDF files
- Taking measurements using the MEASUREGEOM feature
- Creating a 3D conceptual design with freeform mesh models
- Using AutoDesk Seek to find drawing content
- Using dynamic grips to modify non-associative hatch
Skill Level Intermediate
We are going to learn about converting, more specifically, converting splines into polylines. Now, this is something that's never been easy to do and it seems everyone you talked to has their own secret method for making this type of conversion. Well, we don't have to have secrets anymore because AutoCAD 2010 allows us to easily convert our splines into polylines. Let's take a look. On my screen, I have got a drawing of a playground. And this cyan line represents a concrete boundary. Since I am going to have sand around all of my equipment, this boundary is going to help me contain the sand.
Now, the boundary is going to be eight inches wide, and I have already completed my boundary on this side. I would like to do the same thing with this geometry. So I am going to start out by joining all this line work together. To do that, I am going to come up to the Modify panel and launch the PEDIT command, then I'll select this arc and right-click. I'll select the Join option, and I'll window all of my geometry and right-click. If we look at the command line, notice it says only 4 segments were added to the polyline.
Now that looks like it's a problem. So I am going to hit Escape and let's see if we can figure out what went wrong. I am going to hover over my polyline, and notice I can see where it quit joining. Let me hover over this object. I can see that's a spline. Let me come down to this one. This one is also a spline. Unfortunately, we can't join a polyline to a spline. The only way I am going to be able to join this line work together is to convert those splines into polylines. Now, in the past, this was always a problem. Now, it's very easy.
To make the conversion, I'm going to comeback to the Modify panel, and I am going to launch the SPLINEDIT command. I'll then select my spline and notice, there's a new option in the menu that will let me convert this directly into a polyline. All I have to do is specify a precision. The higher the number, the more closely the polyline is going to match the original spline segment. I can enter anything from 0 all the way up to 99. I am going to hit Enter to accept the default of 10, and if I hover over this, we can see that it's now a polyline.
If I select the entity, take a look at all the grips that I have. Generally speaking, what this option does is it matches my geometry by creating several short straight segments. I am going to click Undo a couple of times to turn this back into a spline, and let's convert it again. Now, since we are converting this using the SPLINEDIT command, I can also launch this by double-clicking on the spline and I'll select Convert. This time, I am going to enter a precision of 0, and hit Enter and I'll select this again, and notice, I have fewer grips.
This looks like it's going to work out okay. It's now a polyline and I can join it to the rest of my geometry. Let's take a look at this spline segment down here. Remember that I've mentioned that each person had their own secret method for converting splines into polylines. Well, I used to do it by using the Flatten command. Let's try that. To launch the command, we have to type it in. Flatten allows us, to convert our three- dimensional line work into 2D line work, by the way. I'm going to select my spline and right- click, and then I'll hit Enter because I don't want to remove hidden lines.
If I hover over this entity, we can see it's now a polyline, and if I select it, notice it has far fewer grips. In fact, the Flatten command actually used arc segments to try and match my original geometry. So, in this case, the Flatten command worked better than the new feature in AutoCAD 2010. I am going to deselect this and let's finish our work. I am going to go back and launch the PEDIT command, and let's join this geometry together, and then I'll hit Escape. Now that this is a closed object, we can offset it and my offset distance is going to be .667 and we'll offset this to the outside.
Now, I'm a firm believer in the concept that you should know at least two different ways to do everything. So, if the new Spline Conversion tool in AutoCAD 2010 doesn't give you the results you want, try using the Flatten command. It just might become your first AutoCAD secret.