Cannot subtract from 3D solid?

[SFG13]

Hi,

 

Using 09', I have a solid object (the one in Cyan color) that I want to subtract two circles, the small circle on the top front and the one's in the back. The picture below on the far right shows the subtracted circles. I tried to use subtract a number of times and it didn't change anything. What did I forget or what am I missing?

Rod Gland 3D 4-8-010.dwg

[ReMark]

The circle in the back that you extruded and now want to subtract has been duplicated. When you subtract one the hole doesn't appear to be there because the duplicate cylinder fills the hole. Erase the duplicate.

 

There is no problem with the circle in the front. Switch to a 2D wireframe view and do the subtraction then switch back to the conceptual view. Zoom in on the area to get a better view and make a clean pick.

 

You have a real talent for duplicating geometry. Have you given any consideration to become a fertility doctor? LOL

[SFG13]

I'm still a beginner but how can you tell if the circle in the back was duplicated?

 

If it was, what command can I use to erase it?

Will I be able to use subtract after it's been deleted?

 

With the front circle, I used xedges, and tried to use subtract but it still said "no solids or regions selected." ???

 

What precise commands can I use that will help subtract the back circle and the small circle in the front?

(See attached picture)

[kencaz]

It looks like your circles have not been extruded yet. This would give you that no solids detected error.

 

extrude the circles one at a time either pulling it or you can enter a dimension for the height of the extrusion.

 

Then you should be able to subtract the solids.

 

KC

[ReMark]

I could tell there were two circles in the back because even though I subtracted a circle the hole remained filled. So I windowed the area and lo and behold the outline of a second cylinder was picked up. I erased it and was left with the hole that was created when I did the original subtraction. I verified the results twice.

 

Sequence: I used subtract once then erase once.

 

I was able to create the front hole simply by subtracting the extruded circle. In this location there was (thankfully) only the one.

 

I believe I told you how to do this previously and also recommended that you switch to a 2D wireframe view and zoom in on the area to make your picks. Why won't you follow my instructions?

 

After another look I notice another stray line. Not sure why it is there but it is located along the top of the curve at the back of the object.

[ReMark]

Oh ye of little faith. Behold. I shall open thy eyes.

 

Look at the image below. Let's start at the lower left end.

 

The black arrow points to the "extra" line I found most recently.

 

The next set of objects are two circles. How do I know this? Well, for one, I've made each a different color. And number two, as a test, I erased the inner most red circle and was left only with the blue outer circle.

 

The object next to the two circles only goes to prove you did extrude this part of the geometry correctly. See (inside the black outline) the object is solid.

 

The next two objects prove the existence of the multiple extruded circles I previously mentioned. I colored them differently so they would stand out.

 

 

Now its your turn. Go forth and create. Be careful and be deliberate with your picks and please erase all unnecessary and/or duplicate objects.

 

Thank you.

[SFG13]

I attached my Professor's drawings for you to see how it's done.

 

The extra line (in blue color) is supposed to be there to connect the two larger circles.

 

Why did you erase the inner circle? They're both isocircle D=7/8, R=0.75.

 

I use visualstyles with the 2D wireframe, subtracted the circles, and ended up with the same response saying, "no solids or regions selected."

 

As far as you mentioning "conceptual view," I don't know how to switch to that?

 

Why is it just not working for me?

[Cad64]

It's easier to subtract one object from another when the object you want to subtract is longer than the part you are subtracting from. When both objects are exactly the same size, it's difficult to pick one object over the other. Try stretching out the cylinders as shown below. I changed the colors to help with display purposes. You also need to Union the cyan and green parts before subtracting the cylinder.

[JD Mather]

I attached my Professor's drawings for you to see how it's done......

 

Ask your professor to take a look at the tutorials in my signature. Particularly the presspull command. Your professor is doing too much work. Time is money.

 

(isocircle ? - it looks to me like your professor's instuctions are for 2D, not 3D solids) or am I missing something?

[ReMark]

I erased the extra line because it is NOT needed. I think JDM and Cad64 would agree with me here.

 

I can't believe you're asking about erasing ONE of the extruded circles at the back of the object. It is NOT needed! You only need to have one extruded circle in that position to subtract from the rest of the object to obtain the needed hole. I believe I've mentioned that three times now. You have TWO identical objects occupying the same space.

 

The image you first post uses a visual style called Conceptual. The image I posted above uses a visual style called 2D Wireframe. All visual styles in 2008 should be accessible via the pull-down menu or a toolbar. If you can find one you can find the others.

 

Isocircles? To me that means someone is using the Ellipse command in a 2D isometric plane. I think your "Professor" needs some AutoCAD training himself.

 

Question: Was your professor instructing you to create the object as a Surface?

[ReMark]

For your consideration I submit the following. The image below details the step-by-step progression I took to recreate the object you were asked to draw.

 

The rear hole is shown in cyan; the front hole in red. I used one reference line depicted in green. The final object is shown in magenta.

 

Commands used were line, circle, trim, fillet, copy, move, extrude, and subtract. Isoline was not used.

 

No surfaces were created only solids.

 

It probably took me about 5 minutes to do this including setting up the layers for the circles, reference line and final object. You still continue to override the color of layer "0" which is something I do not agree with.

 

 

I don't know why you continue to struggle so mightly with what should be for most students pretty straight-forward and simple exercises. You continue to make the same mistakes over and over again. Maybe it's the instructor's teaching methods or maybe it is that you fail to fully comprehend the material being presented. My guess is it's a combination of the two.

 

Think carefully about whether or not you should continue to pursue this course of study as the work will only become more difficult.

 

I am going to make a very rare exception in your case for which I may well catch some flack (and I admit it will be deserved) but if you want a copy of the above drawing to see what I did from within AutoCAD you know how to contact me. I offer this in hopes you'll more fully understand the steps one might follow to create such an object.

 

Regards...

 

ReMark

[ReMark]

One additional comment...do you know how to manipulate the UCS to draw in different planes? We are talking in a 3D environment. I am NOT referring to the three standard isoplanes AutoCAD gives you when drawing in isometric mode. Do you understand the difference?

 

Note: Changing the UCS was required in the drawing created above.

[ReMark]

SFG: Have you figured it out yet on your own or are you still stuck?

[SFG13]

Hi ReMark,

 

My Professor was available to show me step by step to make it work, then he told me to do it myself and it turned out great! Thanks for going out of your way and taking the time to create a drawing for me, I really appreciate it!

Rod Guide 3D 4-8-010.dwg

[ReMark]

I admire your perseverance SFG13. Continue to challenge yourself and you'll build skills and confidence as you do. Good job.

 

You're entirely welcomed.