# How do I draw curvy legs in SU?



## garywayne (28 May 2008)

Hi all.

I have drawn a plan, of sorts.





[/img]

How would you draw this? The corners would be rounded. The spherical bits would be round.

Dimensions aren't that important. Also, if you use the bezier curve, (please excuse my spelling), would you explain how you use it. Typing the amount of curves in the box (bottom right) doesn't seem to make any difference.


----------



## SketchUp Guru (28 May 2008)

Gary, I would approach this leg by breaking it apart into sections. The The "spherical bits" would be drawn individually and moved together--probably starting with a single component and making copies. The other parts would be drawn in sections and joined together using Skin. I would certainly split this leg in half or maybe on either side of the central spherical part. The left and right sides would be mirror images of the same component.

If you want to send me the model, I'll have a go at it to see if I can demonstrate it for you.

By the way, regarding Bezier.rb, the number you enter in the VCB after choosing the tool is the "degree". Think of it as the number of spaces between editable ppoints on the curve. You start just as with the Arc tool by setting the first endpoint, the opposite end point and then you set points intermediate points working from the beginning to the end of the curve. If you set the degree to 2 the curve will be some form of a parabolic arc. You'll only have one intermediate point to set.

Bezier curves can be three dimensional. If you are trying to draw a curve that is not 3D, you will likely find it easier to begin with a large surface so you can keep the points coplanar.

After you've drawn the curve you can select it, right click and choose Edit Bezier curve. Then you can modify the curve as desired.


----------



## SketchUp Guru (28 May 2008)

Upon further reflection, I have a question. How rounded are the non-spherical portions? It might work to use Follow Me on those however before doing anything, I would scale the model up by a facotr of 100 or even 1000 to avoid issues with small faces.


----------



## garywayne (29 May 2008)

Hi Dave. Thanks for your reply.

I did my model by drawing the spheres of one side, then joined them together using the "Bezier curve". Which I must say I have big problems controlling. Then, as you say, I mirrored it.

What is "Skin"?

The non-spherical bits. I was hoping to play with them, (once I know how), until it looks right. Obviously it can't be to round because of the pointy stickyout bits.

Regarding scaling up and down. I scaled up my model to draw it, and had more problems un-scaling back to 1:1. 
Would you also be able to explain how to do that? Please.


----------



## SketchUp Guru (29 May 2008)

The 'pointy stickyout bits' do create some problems. Mainly though in the way they would be handled even in the wood. Deciding that will help in figuring out how to tackle it in SU. I can think of several options depending upon how much rounding you need. I could see a slight rounding being indicated by offset edges and then softening the outer edge followed by hiding the offsets. Follow Me could be used but I think you'd need to break the operation into several steps extending the paths and then running Intersect after bringing the parts together. 

Skin is a plugin that creates a skin between the two edges. I'll find the link for you but if you go to the Design. Click. Build. blog you can see an example of it on a table leg in a post I did a few months back.

As far as scaling up and back goes, I think the easiest way is to measure a line of known length with the Tape Measure tool. Then enter the desired dimension. You'll be asked if you wish to resize the model. When you've completed the editing, you can scale back down in exactly the same way.

I find it nice to make a line of some length such as 1" somewhere a bit away from the rest of the model. Then I can measure that for the scaling. I don't need to worry about editing it and it can be deleted later.


----------



## garywayne (29 May 2008)

Here we go. More problems. Sorry guys.

I found a "skin" plugin. I have downloaded "Winzip" evaluation package.

When I extract the plugin I get an error message.
Message says: 

ACCESS IS DENIED.
Unable to create directory C:/program files/Google/ Google SketckUp/SketchUp 6/Plugins

I have tried several plugins.
What do I do?

All suggestions greatly received.

Thanks for your time.


----------



## SketchUp Guru (29 May 2008)

Gary, before unzipping the file, you need to set the location for extracting the file to the Plugins folder. You can see the path in your error message.


----------



## SketchUp Guru (30 May 2008)

Right. Let's see if I can make some sense of this illustration. We'll start at your drawing and work anti-clockwise.

From your drawing I copied out one curve at a time. I only did four of them as an example. Those curves became individual paths for Follow Me. The results of four Follow Me operations using the same profile are shown. Note that it is important to set the profile perpendicular to the first leg of the path. After Follow Me on each of these, I extended them a wee bit with Push/Pull to make sure I'd have geometry for Intersect.

Next we have two views of the geometry after running Intersect on the four parts moved together. There's a fair amount of deleting unneeded geometry, softening and hiding edges. To make it a bit easier to keep my ducks in a row, I worked first on two extrusions intersected with each other. Then I drew the next extrusion and repeated the Intersect, erase, soften and hide operations. Then I started with the process over again. At the top of the image is the profile I used.

To do the spherical parts, I would make a sphere and then use Scale to stretch it out a bit. this would also get intersected.

In all honesty, I don't think I chose the most appropriate profile for the Follow Me operations. I also used the same profile throughout and I'm not certain it works that well.. I think it might be more appropriate to change the profile for different parts.

While drawing this, it occurred to me that the pointy bits might not work so well as drawn. I'm not really sure how they should be done even in wood. Should they come to a rounded point instead of a line? Perhaps the parts of the leg that aren't spherical should have sections that are more nearly circular. There should probably be some sort of "ankle" or another sort of transition into the spherical parts.

Drawing this is certainly a challenge although for me it's more because I don't know what it should look like. You can play with this method and see how you get on.

Earlier I mentioned drawing the leg sections and using Skin to fill in between them. That might work better especially if the section profiles change between areas.

No matter what you do, I think you'll want to ultimately split the leg in half half both across its width as well as in thickness. Make a component of the quarter of the leg and then copy and mirror it to make the rest. I think it'll still be a fairly 'heavy' component but it should be manageable then.

Another idea comes to mind. Perhaps you might consider drawing the leg without the spherical parts--just continue the curves as if the spherical parts aren't there. Soften the edges of that geometry and then make the spherical parts separately, move them into place and do an Intersect. this may not be perfect but it might get the point accros with less time and energy invested in the drawing.

I think this last thing is something that should always ride in the back of your head when modeling. How much detail do you need to draw to get the point across? Don't draw stuff if you can communicate the idea without it.

There. Are you totally confused now?


----------



## garywayne (30 May 2008)

Thanks for that Dave.

I have been playing about with this for the last three and a half hours whilst reading your instructions. Where I am still a very basic SU user, I need to play around for a long time to get used to using the tools. I have never used intersect before. To be honest, I don't know what it does.

I have drawn the four lines and produced four sections. Fitting them together and getting rid of the unwanted bits is something else.

Thanks again Dave. You have been real helpful.


----------



## SketchUp Guru (30 May 2008)

Gary, Intersect with model or Intersect with Selected make the connected geometry intersect. You then delete what you don't need leaving the rest.

Here's a very simple Intersect. One cylinder was moved into the side of the other. After running Intersect, I got what you see in the middle.





As far as fitting them together is concerned, try this. Make the extrusions groups or components until ypou have them positioned. Then explode them before doing the Intersection. Make sure to grab the component with the Move tool at a corner that can be referenced to another corner. Start the move in a direction parallel to an axis as needed. Once the direction is established, hold Shift to lock the direction. Then you can move the cursor to the corresponding point on the other component.

Best wishes on this project.

Dave


----------

