Ok - here's a Japanese bathtub beginners tutorial!
I'll try to give some commentary along the way, so I guess it is a bit verbose.
Make sure you have the latest beta release, version Feb-9-2007.
The first step will be to build the main shape - this will be done by drawing some curves and lofting them.
For drawing the curves, use the Draw curve / Freeform / Control points command. We'll draw half of the curve and then mirror it. When you draw half of something it is important to position the endpoints of the half exactly so that it will be nice when it mirrors. This means placing both the endpoint of the curve right on a line, and also having the second inside point of the curve come off perpendicular to that line. The position of the second inside point controls the ending tangent direction of the curve - if this is not perpendicular to the mirror line, you will have a sharp crease there which you often don't want.
The easiest way to line these things up is to use a feature called a "construction line". The way this works is that when you are inside a drawing command, you normally can click and release to tell the command to accept a new point. But if you click, hold down and drag instead of click and release, you will get a construction line instead - this provides a convenient snapping line for alignment.
So start the Draw curve / Freeform / Control points command. Switch the view to full-screen "Top" view by using the tabs in the bottom bar. Before placing the first point of the curve, click on the origin and drag out a construction line. Place the first point of the curve on the construction line, and then make sure the second one is snapped perpendicular off from it, this should look like this:
Continue placing points, and make sure the last one is snapped perpendicular back down to that construction line:
Now repeat this to draw some other curves - each of these curves is going to become a cross-section of the main bath shape when we loft them, we will be moving them up vertically from one another in just a bit.
If the old curves are getting in your way, you can move it off to the side or select it and use Edit/Hide to temporary hide it from view.
Here I have drawn 3 curves - I just did these pretty quickly, you may want to spend some more time doing this a bit more carefully because the shapes of these curves will directly effect the shape of the bath. Also you can adjust the points of a curve by selecting it and using Edit/Show pts. But be careful to keep the 2nd inside points perpendicular to the axis line if you move stuff around. I want to have the bath kind of slope out a bit so that's why they get longer:
Then I'll tell you what - let's not mirror these yet, let's loft them first and the mirror the lofted surface because it will be easier to edit the surface by tweaking just this half-curve. If we mirrored and joined the curve right now before lofting if we wanted to edit the resulting full curve it would be a bit of a pain to keep it symmetrical, you would have to use scaling on both points on either side of the axis.
So that means the next step is to move the curves to different elevations to prepare for lofting. The smallest one will stay at the bottom to be the base.
There are a couple of ways to move the other curves to different elevations - one way is to use the Split view, and select the curve you want to move in the top view, and then switch to the front view and click on it and drag it upwards. It is also possible to do it inside the 3D view if you drag and move nearby the vertical "z" tracking line, which is what I did here because I like seeing the proportions of working directly in the 3D view pretty often. Note - you need to have "Straight snap" enabled for a lot of this stuff to work, that means that the text "Straight snap" on the bottom toolbar should have an orange highlight on it indicating that it is active. If you have clicked this at some prior point to turn off straight snaps then a bunch of the perpendicular type things won't be happening. You normally want to leave Straight snap and Object snap turned on to provide for precise placement of points. Sometimes you may want to place something in a freeform manner and the snaps might get in your way - that's when you would temporarily turn them off.
Here is what they look like after arranging them in elevation - I have spaced them so that there will be more of a curve near the bottom portion. You can use more curves to get more control, but using too many curves tends to make things wiggly unless you have them arranged just exactly right, so it can be a good idea to use fewer curves here. But maybe one more wouldn't be bad.
Now it's time to build a surface from those curves - there are a variety of different tools for constructing surfaces from curves, in this case we will use Construct / Loft - select those 3 curves, do Construct / Loft, and push "Done", or right-click in a viewport. You can right-click inside a viewport or push the Enter key as different shortcuts for pushing the "Done" button. A lot of commands have different options that you can change or tweak, and you push "Done" to signal that you are finished tweaking things and want to accept the current result and exit the command.
When you are not inside of a command, you are inside of "selection mode" - you use selection mode to select objects and after you have built up your selection you then launch a command that will work on that selection. You can also drag objects and points in selection mode to manipulate them.
Anyway, so we just did a loft so this is what it looks like:
After that select the lofted surface and do Transform/Mirror, pick the 2 endpoints of the bottom curve to get this:
Right now if you were to edit one of those 3 curves that were lofted, the lofted surface will update. We want the mirrored surface to update as well though, and this is possible to turn on by selecting the mirrored surface and using Edit / History / Enable update. By default the results of a mirror don't automatically update when its original object is edited, because this can be kind of surprising for some simple drawing and drafting situations (maybe I should revisit this though). But using Edit / History / Enable update turns the update on. This is good because now the shape can be modified easily - if you manipulate any of the 3 curves (you can drag the entire curve, including changing elevation, or turn on points and manipulate individual points), the loft will update, and then the mirror that is built from the loft will update as well.
This is the point at which the shape is the most tweakable and editable, so if you want to adjust the shape, this is the spot where you want to do that. The next stages after this will break the connection between the curves and the objects. So you probably should save off this version of the model somewhere so you can come back and tweak it more later on if you want. This is not a bad area to spend some time.
I turned on control points for the curves and tweaked them around quite a bit to put a bigger slope on the back, seems like it would be nice to lay back a bit :). Since we are going to shell this later on, you don't want to have too many little bumps and ripples in it (otherwise it tends to make the shelling not work properly), you want it to be pretty smooth and more gradual curves in it rather than little bumps. So that's something to watch out for. I also flared the top out a bit. Here's what I ended with:
That's looking pretty relaxing already! :)
Ok, now it is time to solidify the object - you can select and delete the 3 curves now because we won't be able to use them after this, then select the 2 halves and use Edit/Join to glue them into a single connected object. Now select the joined object and use Construct/Planar to fill in the top and bottom with planes - this turns the object into a complete solid at this point, looking like this:
The next step is to "scoop it out" by shelling. Before running shell, select just the top face of the solid - you do this by doing what is called a "drill-in" selection. A drill-in selection is when you do a second selection click on a surface or solid object to switch from "whole object" selection into a "sub object" selection, which means either a face or an edge. So in this case you want the top face - click once on the solid so that the whole thing is yellow, then click a second time on the top face (not nearby an edge), and then just that face will turn yellow - this will be the face sub-object selection.
When you do shell, any faces that are selected will become openings and the rest of the object will have thickened walls. So once you have only the top face selected, run Construct / Offset / Shell. Now you need to pick a thickness value - you can either type it in, or you can pick 2 points with the mouse and the distance between those points will be the shell thickness. Shelling can be finicky - any little ripples in your object become magnified as shelling tires to do a constant-distance offset away from the existing surfaces - the larger distance that you use tends to magnify any bumps and ripples in the object and if this causes the surface to bunch up together or cross over itself in any way, the shell will fail. So it is not unusual that you may need to shell with smaller values unless you remove some tight bends or ripples in your objects. In my case I tweaked the shape a bit to remove some curvature to make it possible to shell it with a larger distance, I used 6 here - I also decided to go back and lengthen the tub a bit:
So that's the basic form right there. One next thing to finish it up a bit is to fillet the edges so the sharp edges will be rounded. To do this you can either select a whole object which will fillet all sharp edges, or do a sub-object selection and it will only round the edges you pick, or the edges along the borders of the face that you pick. Here I selected the top face and filleted it with a radius of 1.0, then I selected the inside bottom face and filleted it with a larger radius of 5.0 :
I hope this gives you a basic idea of how to approach constructing a bath! You can construct other types of things in a similar manner - draw curves to define some outlines - construct surfaces and solids from those, fillet edges to round off sharp corners...
Please let me know if you get stuck anywhere or have any questions on any particular step.
One other general tip for starting out - get used to moving your view around quite a bit. If you have difficulty picking something or you are running into other stuff, make sure you zoom in or rotate around if you are in the 3D view to get a better angle on the stuff you are working on.
- Michael
