[dougmontgomery]

This Tutorial Thread has a ton of questions and a lot of need helps, but not many tutorials.

This could help some of us because most of the tutorials are on drawing mechanical parts.

Here is an example of what i would like to see, and please if you want to help, take your time and do a several step process.


Draw Part in the UCS coordinate system in the upper right hand quadrant.

Draw a baseball bat example- type shape that is not a true cylinder preferably with a few ellipses and circles.

Extract(boolean subtract) the baseball bat from a rectangle(mold) that has 1/16th index pins in all four corners

Thanks in advance,

I want to make airplane fuselage molds initially and this would help greatly

Doug

[Trotline]

"Be careful what you wish for.."

I've been meaning to get a capture program and make some desktop videos. Sadly for you, you get to be my first victim.



This video goes through making a solid using the <Revolve> function, and using the <Boolean Subtract> function. Hopefully I'll hit on some stuff you actually wanted to know..

Disclaimer: I don't represent that this is the best way to do it. In fact, I deny making this video. That's not my voice, it's a clever imitation. Whoever came up with this gonzo load of crap ought to go back to scratching on cave walls with charred sticks.

Luke

[dougmontgomery]

Trotline,
Thank you for this, It is exactly the kind of tutorial I wanted. +1
I hope you continue to make these, simple and straight forward, and clear on your verbage.
Please do not remove once you start, this could be a good reference for people, and me of course.

Most of the tutorials I have watched get too complex for applications I do not need yet.

Is this your first one? will you plan on building a series on youtube?

thanks for all your help!!!
doug

[dougmontgomery]

So I managed to do the first tutorial, quick trim did not work as smooth and simple as I wanted. Both tags hanging below, one trimmed smoothly, the other wanted to take out my whole interpolated line.

Tutorial 2: are you up for it???
Making a Surface revolve from given points.

[Trotline]

Sure, I'll try to knock something together. Do bear in mind though, that I'm a greenhorn at BobCAD, learning by trial & error, watching videos, and reading these forums. Do you have BobArt? There's a tool in there, <2-Rail Sweep>, that's really better suited to what you want to make than the <Revolve> tool, and it's less clunky to use. If you do have BobArt, I'll put together a tutorial on that for you, as well.

There are some good videos out there. Have you seen Sorin's collection for V24? Index of /free/Bobcad V24 There are a ton of good tips and tricks in there.

Luke

[jrmach]

bobcad v24 videos - YouTube

http://www.bobcad.com/wp-content/med...ted-Manual.pdf

[dougmontgomery]

Luke, i really want to learn this in bobcad, once i get the solid i may need to boolean subtract a wing saddle or modifications. I will look through the other tutorials.

[jrmach]

Burr has made some excellent tutorials over the years on things right up your alley.Maybe he can share some of them.

[SeanDa]

The easiest way that I have found to do this is to import a picture of a bat, draw a line straight down the center. Then use a spline to draw the outline of the bat and then revolve 360 with caps. Then draw the base solid and use solid boolean subtract, and you will have your bat mold. I have attached a part that shows what the finished results look this way.

[Trotline]

Here's a video working off the points you specified in the .pdf. A couple of things are worth mentioning. I chose to use flat bulkheads fore and aft, but it would work exactly the same if I'd drawn arcs instead of lines, and thus revolved nose and tail cones instead of bulkheads. Toward the end of the video, I'm messing with the viewing angles, trying to see things. A much better way of doing things is to use layers, and keep things like the base geometry and the surfaces / solids separated. I just didn't want to confuse things or make the video any longer, so you get to watch me swing the camera around, instead.



This video felt more crowded than the other one. I hope it's not too hurried or disjointed.

Luke

[dougmontgomery]

Luke, You definitely have an aewsome Radio Voice- This looks great- Did you import the Points in or just select Points to place them in the UCS?

Will do this one tonight!

Thanks for all your help! I like this approach directly realted to what I need to learn,over my V25 videos because It will save me tons of time trying to find that..." where was that again"


Greatly appreciated

Doug

[Trotline]

I just jotted the coordinates down from the .pdf you posted, then used <Points> [Coordinates] to place them manually, since there weren't many of them. Doing tutorials is something I've been meaning to start on for a while now. This is good practice, and hopefully I'll get better over time. Also, addressing specific questions like this makes me jump into processes that I haven't really visited before. You learn a lot that way!

Luke

[dougmontgomery]

So i modeled the fuse off of thr given coordinates and added a .350 radius to the front which i quick trimmed back to the x,0.

Then revolved and it worked. Definitely needs more coordinates to smooth out.

So i have another desire, i tried to open a .dxf and use it but it did not work well.

Open .dxf

Either redraw on layers or use as is, close all lines.

Doug

[dougmontgomery]

I once again thought this should be easy, nope- 2-3 hours and still couldn't get it to revolve or surface

Went to the UCS side plane

Other>Ellipse select size

Length 40"

Large end
Major .775
Minor .675

Small end
Major .375
Minor .300

Once the solid was made I was going subtract it from 3" mold on the midline as Luke showed us before.

doug

[Trotline]

It can be maddening, at first, for sure. The system can seem extremely finicky. More often than not, I'm learning that problems come down to "bad geometry". It can be a tiny thing like 2 lines that look joined until you zoom in so far that a gnat's behind looks like Jupiter. It can be a microscopic line segment tucked directly beneath another line. That's likely the problem you had with an imported .DXF file, by the way. BobCAD handles .dxfs fine, but bad geometry will still cause failures.

Under <Utilities> [Reorganize], there are some tools that will go a long was toward cleaning that sort of thing up. Another thing to do is frequently Chain Select, (Shift + Left Click) to make sure that lines you expect to be joined are in fact joined.

And sometimes, it's something truly weird. I've had complex Vcarves that would throw crazy loops into the toolpaths until I just moved a seemingly random vertex nearby. Some of these things, you'll just have to get a feel for. Our own distinct workstyles tend to make some errors more common for some people, I think.

Luke

[dougmontgomery]

Using the skin feature, I have the shape half drawn and my intent was to place the skin on it then mirror if needed to do the subtract.

How do I join all the segments in the ellipses?

When trying to place the skin on as shown in the tutorials, I cant seem to get get the arrows place correctly with the segments-

What am i missing here?


doug

[Trotline]

Beats me. Whatever the problem is, I share it. I've never gotten <Skin> to work worth a flip. Not sure what I've been doing wrong, but I also have a tough time with it. Maybe someone else can point us both in the right direction.

I generally use 2-Rail sweep in BobArt to accomplish that sort of thing. It works very well, and allows cross-sectional morphing. The downside is that once you get an [Emboss] done, you're there. There's not much manipulation possible after the fact, as far as I can tell. That makes the placement, etc. crucial to get right when you start. I'll post a video on that before long.

Luke

[Trotline]

Eureka! Sorin once again has come to the rescue. I vaguely recalled that he had a video on the <Skin> function, so I went back and watched it. Doug, I can't recommend those videos highly enough. The guy makes his living going around teaching this stuff, and he's really, really good at it. Things like how to keep chain selections all oriented, with the arrows lined up and at the endpoints, for instance, are well and thoroughly covered. The videos are well organized, and even come packaged with their own player. They're located at Index of /free/Bobcad V24 and they're free.

My basic malfunction was that I was applying the steps from Embossing, which I've been doing a lot of, to <Skin> and they're all wrong. First, the cross sections must be joined to the rails, they must also be oriented as they will be in the final skin, and the rails must be divided at the points of intersection. Once all that got sorted, I was skinning like a champ.

Luke

[dougmontgomery]

These are great videos, I a have watched 3 of them so far....Contour should work great.

Doug

[jrmach]

Did you get it to work?I was going to load a pic,,But the Zone won't let me.I think they want me to re-size Pic.Hope they get this fixed,because going into another app. just to re-size is ridiculous.

Just tried re-sizing pic.,,that did not work.Anybody know what's going on?

I do it a different way then::http://postimage.org/image/ek0ep77zj/