Isometric drawing to 3D question

[JD Mather]

... the 30° doesn't follow the plane of the geometry, but looks to be from the current view, ...

 

The 84 was obviously wrong, wrong dimension and wrong location.

Superimposing the image and using your tip on the origin of the 30° mistake - this is what I came up with as the probable design intent.

 

 

A good reason to abandon isometric 2D drawing.

Generate views from the single source of truth - the 3D model.

 

Edited July 22, 2014 by JD Mather

[ReMark]

Works for me.

[MinaRAI]

Oh guys thanks for the very very detailed help. The drawing exercise I downloaded did not state the units to be used. I just did tis in metric acadiso drawing. It seems to be in inches...had that thought back then but just continued to draw it to altogether.

 

Please bear with me as I went really slow trying to remember what I learned back from drawing 101 in school. My drawing is in error.

 

Looking closely it is and should be 64mm.

 

Might I ask a very newbie question along this line..? How did you guys knew that the height is wrong again..please bear with me on this please...

 

The angles I had issues when I was trying to draw the isometric view. From there it all went sideways....I need to do this again from scratch based on your guide drawings and teachings. I have saved them in a usb. Thanks guys for helping out a self-studier.

 

As mentioned earlier in another post, please bear with me as I am currently having trouble with where to go for self-study at the moment as the previous location I did went is having problems. Might take me a while to search another loaction near my area. I will try to take a stab at this one again and start from scracth. Afterwards post here again.

 

I'd like to say thanks again to you guys (JD, Ske_Me, Denimoth, Titi95, Patrick Hughes, CaddJax and ReMark) for all the help. Allow me sometime and I will be back here to reply with a recreated drawing. Thank you for bearing with me

[JD Mather]

... It seems to be in inches...

 

Where did you get that information? The original is in mm. (in any case, doesn't matter for this problem)

 

 

Looking closely it is and should be 64mm.

 

Where did you get this information? I looked at this thing pretty closely. Probably spent a couple of hours on it. I do not see a 64mm anywhere in the solution I suggested?

 

I placed the image and superimposed my solution over your original image to reverse engineer the solution and used logic to figure out where the original designer made the mistake with the angle dimensions.

[CaddJax]

 

I create a rectangle 88x50mm and then press-pulled it to a height of 18mm. I then created another rectangle 88x50mm press-pulled it to a height of 66mm. From there I created some lines to make the cross and again used press-pull to discard the remainder.

 

I'm at a complete loss with the different answers being posted here. Based off of his instruction and not his drawing (which he said he's not sure about) then the total height is either 66mm or 84mm. I did misunderstand that he wanted to subtract a pyramid, I just took a slice out at the specified angle.

 

Will post a pic later when I have a chance to redraw.

[JD Mather]

Will post a pic later when I have a chance to redraw.

 

Better yet - attach your dwg file.

[CaddJax]

Better yet - attach your dwg file.

 

This is it before I subtract the triangle.

3d Model.dwg

[Titi95]

Where did you get this information? I looked at this thing pretty closely. Probably spent a couple of hours on it. I do not see a 64mm anywhere in the solution I suggested?

 

I placed the image and superimposed my solution over your original image to reverse engineer the solution and used logic to figure out where the original designer made the mistake with the angle dimensions.

 

for me it's 84 ...

[CaddJax]

Better yet - attach your dwg file.

 

And here it is with all of my extractions based on his drawing

3d Model - Copy.dwg

[JD Mather]

for me it's 84 ...

 

Your "solution" is obviously wrong.

 

1. Those two points are not on the same plane - you cannot place a dimension between those two points in an isometric drawing.

2. It becomes obvious that your solution is incorrect when you compare to the original.

 

If it is 84 for you - what is the distance shown here on the front plane of the part?

 

 

See Post #17 for the source of that mistake.

[JD Mather]

And here it is with all of my extractions based on his drawing

 

Your "solution" is obviously incorrect. The source of all errors have been explained logically and the true dimensions given.

This is an example of someone who got confused about true dimensioning of a isometric 2D drawing.

Your "solution" does not even look like the original.

[CaddJax]

Your "solution" is obviously incorrect. The source of all errors have been explained logically and the true dimensions given.

This is an example of someone who got confused about true dimensioning of a isometric 2D drawing.

Your "solution" does not even look like the original.

 

Well.... I kind of looked at it this way and came up with 84 H overall as well...

 

I create a rectangle 88x50mm and then press-pulled it to a height of 18mm.

 

18mm H base

 

I then created another rectangle 88x50mm press-pulled it to a height of 66mm.

 

66mm H Cross

 

The last action I did was to move/place the object onto the base.

 

18mm Base + 66mm Cross = 84mm Overall

 

I know he fudged his dimension lines, but in this case he screwed it up so bad it was right.

 

Any questions?

[JD Mather]

...

66mm H Cross

18mm Base + 66mm Cross = 84mm Overall

Any questions?

 

My question is - "Where did your 66mm come from - I do not see it on the drawing."

All other dimensions have been logically explained.

[JD Mather]

I'm at a complete loss with the different answers being posted here. Based off of his instruction and not his drawing...

 

I am beginner and... ...I then created another rectangle 88x50mm press-pulled it to a height of 66mm....

 

These are not instructions, this is a description of what the OP (a beginner) did incorrectly. The original drawing is the source of information you should be referencing.

[CaddJax]

Which is the 'original' drawing?

 

Back to the first post.....

[Titi95]

Your "solution" is obviously wrong.

 

1. Those two points are not on the same plane - you cannot place a dimension between those two points in an isometric drawing.

2. It becomes obvious that your solution is incorrect when you compare to the original.

 

If it is 84 for you - what is the distance shown here on the front plane of the part?

[ATTACH]50103[/ATTACH]

 

 

See Post #17 for the source of that mistake.

 

I was only confirming what is writing, but I also confirm that the coast is misplaced

making the original plan must

[JD Mather]

Which is the 'original' drawing?

 

Back to the first post.....

 

Yes, of course!

 

Someone has a problem - you have to analyze the problem.

 

You can't just say, "Well that is the information you gave me - I'm just going to push ahead. If my solution to your problem is wrong - it is because you gave me the wrong information."

 

That is not how problems are solved - that only ensures failure to recognize and correct the problem.

 

I will try one more time:

 

 

Points A and B are in the same plane - so you can specify true dimension between these two points.

Points A and B are on the Front plane.

Points B and C are on the Top plane. Points B and C cannot be different heights?

 

Points A and C are not in the same plane. This is a problem. You cannot ignore this first problem. Post #17 indicated the source of the error.

 

Following the logic from Post #17 the source of the error in the angle made logical sense.

 

... I can't really explain it, my french brain would explode trying to translate it to english....

I can't explain it any better. Wish I could. Maybe someone else here can help with that.

I've tried my best, if this doesn't work - I give up.

 

Once the errors (and their sources) were identified - (unique) solution of the problem was fairly trivial.

 

Using the scientific method - attempt to disprove the solution I offered. I am OK with that. I want to identify the correct solution. By what logic is it not correct?

Edited July 28, 2014 by JD Mather

[Denimoth]

I'm referencing my old school style of manually drawing an isometric drawing using the ol' pencil and paper. But I think the problem could have been avoided if you (the OP) changed the order of how you drew the geometry. My guess is you jumped right into the complex shape from the bottom up.

 

1. Start with drawing the basic shape, which would be a cube that is 88 in length, 50 in depth and 84 (or 64) in height. You can't possibly mess that up.

2. Once the cube is drawn, THEN you can modify the geometry by drawing out parallel lines at the dimensions you showed for all those cutouts.

3. Trim/erase the lines that aren't needed and you should come up with the proper finished sketch. I would do this after I finished dimensioning the shape as the guidelines will allow you to get the proper measurements.

 

That's how it's done in 2D.

[MinaRAI]

Hi guys,

 

I finally found the same drawing exercise that I downloaded. I lost it somewhere but a friend had an old Acad 2000 book which had the same drawing. Here it is. As seen I have erred in drawing it. The total height is 56mm not 64mm(as I have said before). I did not check what I made and when I placed the dims it was 84mm. Wrong procedure. Do bear with a newbie please.

 

Pardon me for the error and confusion. I misplaced the original cad exercise drawing and all I had left was the drawing print I plotted. All that was left was a vague memory. So sorry I do not have a desktop that's working also and i am just renting a pc in an internet cafe. All files are in a usb but I seem to have deleted it. Can't recover from the previous location where I started studying as they have problems there. More so they have DeepFreeze and the file may have been deleted already.

 

So here it is guys. It took some time locating this drawing in google and youtube (from where I got it) to no avail.

 

 

In connection with this may I ask again some elementary questions (please do bear with me).

 

I am having problems drawing that triangle and subtracting it in 3D Model. What approach will I have to do it?

 

I need to create that triangle and extrude it right?

 

How can I position it to the 3D model? Move and paste it?

 

If I use slice, how can I slice it? I do not know where to place the points so as to slice it at an angle of 45deg...

 

As I am typing this one I also am trying to search for a video at youtube but could not find anything with a slice that would fit my problem...

 

Thanks again

[Denimoth]

There is no need to draw and extrude a triangle to make the cut shown. SLICE is all you need. To determine where the point A is located, draw a line along the bottom front edge of the geometry, then use ROTATE3D. For ROTATE3D, I'd suggest you first try using the 2points option (or the "Z axis vector" in the drop down menu) pick point C for the first point selection, and pick the other end of the bottom edge at the back (where the 50 dimension is referenced). That will tell AutoCAD that you want your line to rotate along the axis you just defined. When it asks for the rotation value, type 45. Point A doesn't exactly need to align with the top projected edge for SLICE to work. Anywhere along the guideline you just drew and rotated will work.

 

Now use SLICE, use the 3 points option, and pick the bottom corner (point C), the rear top corner (point B, you might have to draw extension lines to find that point) and anywhere along your guideline for your third point (equivalent to point A). When done, erase the excess solid and guideline.

 

With AutoCAD, there are multiple ways of doing things that will get you the same results. You should also research how to change your UCS orientation to use the regular ROTATE command instead of ROTATE3D. This can be very useful when drawing 3D objects. Experiment with the options that UCS command offers, including the Face option. You can even pick 3 points to determine the origin, the direction of the X axis, and the direction of the Y axis.

 

You're profile says you are using AutoCAD 2010. If so, check the help files and in the Contents tab, go to User's Guide > Create and Modify Objects > Use Precision Tools > Use Coordinates and Coordinate Systems (UCS) > Specify Workplanes in 3D (UCS), and read up on the information provided there to explain how to use UCS to be effective in 3D modelling.