Modeling Willamette Blocks

[Ray Dunakin]

For instance, how are you supposed to know what size your model is, if there's no rulers?

I model everything full scale or 1:1, then I scale it down to make the STL file. That way I can make the parts any scale I want.

Not to hijack your thread or anything, but how do you do that if there's no frame of reference? Whether you're modeling 1:1 or some other scale you still need some way of determining the length, width and height of the objects you're drawing.

[marc_reusser]

Ray; Some of the catalogs have basic dimensions of the blocks...some even have section drawings or line elevations. You then just take this info, and from there you can extrapolate the other dimensions/info. (or you can always measure a real one...there are several places on the West Coast that these are lying around in museums and such.)...from there you can simply set the scale, and units of your drawing environment/file, and start drawing. IMO, like Dan noted, it is always best to draw in 1:1 (full scale) whenever you can, and the just scale your "out-put" (be it a 3D printed model, or view-port window in a 2D sheet, or a machining file, etc.).

Dan; I'll drop you a note. I made a mistake, although I do have a WISCo catalog, the block catalog I was thingking of was a Y.I.W. (Young Iron Works)...of same era.

Marc

[dandy97]

Ray, I probably should have been more specific, but Marc is exactly right. For instance the Willamette catalog has a few basic dimensions along with pictures of each item. You only need one or two known dimensions in order to determine the scale of a photograph. From there you can measure most of the features, anyway that's how I do it. Some of it is an educated guess. However, we are making models and as long as it looks and feels right that's all that really matters, in my opinion anyway.

Dan

[Ray Dunakin]

Sorry, I guess I'm not making myself clear. What I'm trying to say is that there's no frame of reference in the software -- no rulers, grids, etc. Even drawing something as simple as an eight-foot long 2x4 is impossible if you have no way, in the program, to determine the dimensions of what you just drew.

When I was using my ancient 3D modeling/animation app it was easy. I could just drop in a cube, stretch it out to 2" in one direction, 4" in another direction, and 96" in third direction, using the rulers to measure it. I don't know whether the CAD I'm using (TurboCAD) is really lame, or I'm just an idiot, but I can't find any way to tell what size anything is within the program.

[dandy97]

I don't know whether the CAD I'm using (TurboCAD) is really lame, or I'm just an idiot, but I can't find any way to tell what size anything is within the program.

Ohhhh, now I get it. Yes all of the CAD programs that I use have a way of defining the dimensions of whatever you are drawing. I'm not familiar with TurboCAD, but it is kind of useless if you can't specify the size of anything.

[eTraxx]

Turbocad. Displaying the Dimensions toolbar

http://www3.turbocadcommunity.com/tiki-index.php?page=Dimensions

[marc_reusser]

Ray,

All CAD & 3D programs that I have worked in have a standard default mode of 1:1 in their model space ("model space" is the realm in which the drawing is being created). The user can change this if desired, in the menu or properties (usually located in a pull down menu at the top, and quite often appearing as a "setup" box/menu when you create a new drawing file)

If you have your screen/program desk top, set up properly, there should be numerous comands and pull-down or fly-out menues plastered in the borders at the top or sides of your CAD program, many programs rectangular disply or information boxes at the bottom border...theses boxes will show active/real time drawing information with certain commands....such as length of a line segment as you move the cursor in "line" mode. Some programs will have this box/information at the cursor, so as you pull the line across the screen it shows you exactly the length at any given moment.  You can also draw a a certain length by entering the lenth you want, once the command and start point has been activated...and all you need to do is move the cursor slightly in the direction you want the line to go. A basic example sequence to do this would be:

Command/Menu item: "Line"
Select start point
Move cursor in direction you want line to go
Enter dimension/length you want line to be

There are many other ways to do this, as well as "offsetting" lines as guides, creating"guidelines", or "stretching lines". It generally depends on what the CAD operators preferences are, and what works best/quickest/easiest/most accurate, at the given moment and for the given need.

There should also be a "ruler", or "dimension" or "tape measure" (or whatever it may be called in the specific program) that allows you to measure the length of a line or a distance of any sort. A basic sequence for this might be:

Command/Menu Item: "Dimension"
Select item on screen or "start point"
Pull cursor the desired length/distance you want to measure.
End command at end point of measurement by mouse click.
Distance/Dimension should show in "information box" at bottom of screen or at cursor (depending on program and set-up)

Another way to find out the Properties of a line or object (such as length, width, aread, volume, location in space on x/y/z axis) is to select the object, and then type or select "list" or "properties" (or whatever the command is called in the specific program), and it will give you all the info associated with that line/item/object.

Every CAD operator works a bit differently, and will taylor the screen and program settings to suit their needs, some prefer using menues, some prefer using typed commands, some use a combination, others will write LSP commands to do multiple movements/sequences in one typed entry......it all depends on personal preference, experience, and the type of work being performed.

IMO, most CAD programs are way too complicated for most people that just want to try it out, or use it every now and then for a simple line drawing, especially if they have never been a draftsman, or properly learned to draw/draft and layout a drawing. (and IMO most people have no business using them...sort of like me deciding I want to try driving a bulldozer with no experience  ).  By far, most people I run across that have problems (and this is in no way meant towards you) have them because they never learned the basic elements of drafting and set-up (I am talking in pencil & paper, old school...and no, one or two classes back in high school does not count  ), and because they expect the program to perform some kind of magic, or miracles, making drawing easier and solving all the problems for them. I also find an issue to be that some simply cannot think sequentially once they get on a machine, or they don't understand/grasp the concept of "model space" and 1:1 scale on their desktop monitor.

The above is why I advocate and highly recommend programs like Google SketchUp. It may not be as fancy as other CAD and #D programs, but it has very basic and easy to understand menus/commands, and it functions in a very intuitive and simple manner. They have very good online tutorials, and very clear and easy to understand "help" menu responses. I still however recommend picking (or printing out from online) a user manual ....reading it.....and having it at hand when working.



....but I digress from he subject of this thread.



Marc

[Ray Dunakin]

Thanks guys! I'll give it another shot. Sorry again for diverting the thread.

[eTraxx]

I've never noticed that people mind threads that wander all over the place. Makes them interesting.

[dandy97]

I've never noticed that people mind threads that wander all over the place. Makes them interesting.

I for one, don't mind.

Marc, nice write up on what CAD is all about. I could have not explained it better.

[JohnP]

Ray, I use TurboCAD, for five or six years now. For my bridge parts I draw them in model scale. I do not scale down full size drawings to model scale. I haven't tried but because the model parts require different thicknesses etc so it doesn't help anyway.

When drawing a line you can specify the length in the dimension box at the screen bottom. As you pull the line that number changes, but you can tab into the entry space and specify the length. To start a drawing I usually draw a few lines for the outside of a part, then use offsets and copies to make more lines.

TurboCAD Deluxe is nice for the money, does more than SketchUp and is more CAD-familiar that SU (if you ever spend the big bucks for AutoCAD or Solid Works the transition will be easier).

Gotta go, I'm at work . PM with more questions if you want.

John

[W.P. Rayner]

Ray, I think it's just a matter of spending some time messing with the software application to learn it. I've used VectorWorks (for 2D work) and Cobalt (for 3D work) for years now. Both applications have dialogue boxes and menu windows to set dimensions for whatever it is I'm drawing. I can draw an object, line, circle, curve, whatever, and then specify the dimensions and the application will resize the element accordingly or I can specify the dimensions first and the application will draw the object as specified. I can also go back and change dimensions as necessary or desired and the software will redraw the element. A very useful tip is to set a beginning reference point, zero on all axis, and position your drawing elements relative to that point... very handy when drawing structures. Most applications will allow you to specify numerically the location of any element relative to your reference point.

You should also be able to set the precision of the drawing by specifying the number of decimal points, usually in Preferences. I generally work to four decimal points but have on occasion worked to six or seven if greater accuracy was needed. You should also be able to adjust settings such as snap distance and snap radius which can help with selecting and lining up drawing elements relative to your reference point. A few hours experimenting drawing simple objects (cubes, rectangles, triangles and circles) and adjusting settings should help make you more comfortable with the application.

Both applications I use incorporate layers to separate the various elements of the drawing, allowing you to work on one element of the drawing without affecting any of the others. This usually helps speed up the computing process as well. In VectorWorks I generally use a separate layer for the sheet layout which is 1:1 scale, and other layers for the objects to be drawn, dimensions, notes and so on. A good feature is that each layer can have a different scale, so while the sheet layout, notes and so on are all 1:1, the drawing itself may be 1:48, 1:24 or whatever. In Cobalt I draw everything full-size and separate the distinct elements to their own layer, then apply a scaling factor when outputting files for Rapid Prototyping. This way I only have to draw the object once and I let the computer handle all the mathematical operations... a real plus for those of us who are mathematically challenged!

Paul