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Isometric drawing to 3D question


MinaRAI

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I am beginner and am self-studying AutoCAD 2010 as of the moment. I am really a beginner and just constructed my first drawing as after stopping self-study last 2007(that was with AutoCAD 2008). Anyway, kindly look at the isometric image(dims are in MM). I have drawn (which I saw in the internet). I would like to draw that in 3D Modeling.

 

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.

 

Now I did not went far and in fact I could not think of a way to do the cut-off of the cross as seen in the isometric image. The last action I did was to move/place the object onto the base.

 

Now for the isometric drawing I just drew a 32deg angle from the base and extended it. The same was for the opposite. I the drew an intersecting line thus the triangle. Trimmed/deleted the non-needed lines.

 

I would like to learn how to do it with a solid. Please bear with me as I am not that technical now..(finished an associate degree in Mechanical eons ago but tsk.... I can draw that using pen/pencil paper but in AutoCAD I am a bit slow. I only learn through books / some videos. Mostly I learn on my own/own free time. As of the moment I have no means for a proper education on AutoCAD because of plain economics. I'd like to learn further so I started again.

 

Also if you can see in the isometric drawing the dimensions text is not aligned with the dim lines. I am also at a loss how to do that...At first the dim lines with the text started out as not aligned. So I clicked Annotation>Dimensions>Dime edit>Oblique and type in the angle which is either 150 / 90 / 30 (that's correct in isometric right..?). I was able to align the dims but the text I cannot.

 

If you guys be so kindly help me also with that please....

 

PS,

 

As mentioned I am slow in AutoCAD as I am a self-studier(just really started out with ver 2010 and just actually learning to use the ribbon!). If possible can you guys reply or give some tips via a step-by-step scenario so I can follow..? Think of me as a kid learner... :)

 

Thanks and hope for understanding :)

 

 

N1zKV8z.png

 

x8KIMYK.png

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Draw the 3D triangle then subtract it from your model or extrude a line (at the proper angle) creating a surface and use this as your cutting plane via the SLICE command.

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Welcome to the CADTutor Forum Mina. :)

 

Check out this link http://www.mycadsite.com/ , it is a very good free course for online users.

I learned a great deal, when I was just starting out about 5 years ago, from this site.

The progression is very logical and the lessons broken down into small enough segments,

that it will help you get up to speed very quickly. No doubt you are aware that if you go

to the CADTutor HOME page, there are lots of other great tutorials, both written and videos available at no charge.

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@Dadgad,

 

Thanks I will try to check and see.

 

@ReMark,

 

Will try that and be back here.

 

Thanks for the help. Be back here.

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Can't seem to make that 3D triangle correctly :(..... I managed to make a pyramid and subtracted it from the base but I did that not with precision. I just experimented on it....Is there a proper way to do it...? Unlike in the Isometric drawing you can just draw the triangle via the 45deg angle (30 seems to be wrong as I drawn it again) I can't draw that same triangle and move/place it properly :(

 

Is there a free 3D tutorial video that I can download that I can use for this type of problem I have...?

 

Thanks again all!

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Can't seem to make that 3D triangle correctly ...

 

Attach your attempt here (*.dwg file).

You must become the master of the User Coordinate System (UCS) to master 3D modeling.

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JD is correct - in order to work in 3D with AutoCAD you must master the UCS.

 

 

So, the first thing you must do is turn your UCS Icon on.

 

 

Now, you have to understand that AutoCAD will want to always draw on the XY plane of the current UCS so here is how you draw the triangle.

 

 

Align your XY plane with one of the surfaces to construct the 30 degree angle and draw a line sufficiently long enough to reach beyond the object height.

 

 

Realign your UCS to the other surface and construct the other 30 degree line to the same length (height).

 

 

Now connect the endpoints with a third line. There is your triangle and with this you can now slice your solid body.

 

 

Issue the Slice command and press enter to choose the 3-pont option. Your first pick will be the midpoint of the connecting line, your second pick point will be the vertex of the two 30 degree lines, and your third point will the end of the connecting line. Finally accept the result which allows you to confirm the slice completed properly and then delete the piece you don't need.

 

 

Return your UCS to World.

 

 

Watch out for dynamic UCS You might want to turn that off.

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If you're going to outline the triangular plane, skip the extrusion process. Simply use the Slice command and use the 3 point option. Click each point of the triangular plane and presto. You actually don't even need to connect the two lines to make a triangle as Patrick suggested.

 

I would have done:

 

1. Draw the base geometry as you have done. Keep in mind the height of the geometry is specified as being "84".

2. Draw a guide line along both sides of the geometry (lets call it the X and Y axis), and rotate it upwards at 30° (I used Rotate3d command and used the X and Y axis accordingly, otherwise use the 2 points to determine the axis of rotation). Length of line is irrelevant, as long as you can see where the end point is.

3. Use Slice command and use the 3 point option. Order of the points you will select doesn't matter. Select the end point of each guideline that was rotated at 30°, and select the intersection of the guidelines (that bottom corner where the point of the triangular plane starts).

4. Erase the solid bit that is no longer required, and erase the two guidelines.

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TwiceAsSlice.PNG

I contend it would be more like this. I don't believe the image on the left in post #1 of the OP is shown at the actual height.

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Denimoth: May we see what you ended up with?

 

I see what you did there. The sketch by the OP was a little misleading. the 30° doesn't follow the plane of the geometry, but looks to be from the current view, as if you were drawing it from a flatshot of the 3D model. Simple enough fix though. Orient the geometry, then set the UCS to View. Then Slice using the View option and pick that bottom corner of the triangular plane.

 

Actually, my results are still a little messy. I'm missing something here. Let me look into it some more. My work can wait...

 

Edit:

 

Okay, I agree with Remark that the height on the sketch provided by the OP isn't accurate. The height is incorrect. Therefore, there's no way to reproduce the end result if you can't draw the geometry properly. I get the following with a height of 84 units in the Z axis.

 

c19f17.jpg

 

Here's what I did after drawing the base geometry following the OP's sketch (my eyes hurt from squinting).

1. I oriented the view by using the view cube (top right corner of the image).

2. Set my UCS using the View option.

3. Sliced the solid using the View option, by selecting the bottom corner of the geometry when prompted for a point selection.

4. Deleted excess solid material (this step can be avoided by clicking on a point of the geometry you want to keep when you're prompted to select a side or keep both).

 

P.S. I hate imageshack...

 

Edit #2:

 

I should clarify the step above only works because the specified angles shown for the cut is 30°, which works within the rules of isometric drawing views. If the angles were anything other than 30°, I'd go with a similar method outlined in my first post, but with a couple of changes. If the angles were, say, 34° and 23° (left to right, and completely random numbers). I would have instead done:

1. Drawn the base geometry

2. Change your display to that of an isometric view using the View Cube or other method.

3. Change the UCS orientation using the View option, and select the bottom corner of the geometry, where the point of the triangular plane touches.

Now this is important!

4. Draw a polyline, NOT A LINE! Starting point of the polyline should be that same bottom corner as used in step 3. The end point of the polyline should snap to the opposite end of one side of your geometry (it's hard to explain, but lets say it's along the left side bottom edge). The polyline is drawn using the current UCS (turn off Dynamic UCS for these steps), meaning the X and Y values of the endpoints change, but not the Z axis. That Z axis will always match the start point of your polyline. Once drawn, rotate the line at 34° (as per my example used for the left side).

5. Repeat step 4, but follow the right bottom edge, and rotate that line at 23°.

6. Now slice using 3 point option, select the end points of your two guidelines and the bottom corner (the point of the triangular plane) and discard the excess solid and guidelines when done.

Edited by Denimoth
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Titi: I don't think your end result reflects what is shown in the image to the right in post number 1 by the OP.

my representations are good

this is the model that is not the scale

Denimoth finds the same result for 45 °

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I think the images are pictorially correct but I have my doubts about the angle. I also think you have cut the top portion of the model back too far.

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You've done generally well with your isometric drawing, the only real issue is your vertical dimension of 84. I think I understand where the confusion is. The top edge of your drawing needs to be projected to the same plane as the bottom edge you are dimensioning from. I can't really explain it, my french brain would explode trying to translate it to english. But look at the drawing I've attached to see how the top edge should have been projected in order to obtain the proper vertical dimension. Or vice versa if 84 is the correct dimension, then measure 84 from the same plane, and then project a line at 30° (for isometric drawing).

 

Slice Iso-001.jpg

 

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

Edited by Denimoth
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Maybe it's just me but the fuzzy dimension for height looks like it is 64 not 84. If you look at the base length compared to the height there is a big difference. Was this done in metric or decimal inches. The OP said it was metric but it could be inches.

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Imperial or metric wouldn't have made a difference, as long as you are using the same for the entire model. 1 unit in mm or inches still equals 1 unit in AutoCAD. The only difference would be the scale of the object.

 

I had considered the dimension to be something else and had tried it using 64 and even 54, but the end result was still significantly different from the OP's isometric drawing. Those of us that have drawn isometric drawings on paper can spot the error if you look closely enough. It even took me a while to figure it out. The OP drew the top edge near the middle of the geometry parallel with the bottom edge at 84 in height. Works great on paper, but can never be reproduced in an actual 3D model. You need to make extensive use of vertical and angular guide lines, then find out where they meet up to know where to draw the proper shape.

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Ummmm.... If he drew that as an iso and used the dimalign command, then his 84/64 is a diagonal dimension and not just a vertical - based on his grips.

 

To get the true vertical dimension, the dim's upper grip would be in open space somewhere along where the z-axis crosses the x-plane.

 

Edit: I'm not getting anything near what most of you are, and this is something that I do daily.

 

5iWcADF.png

Edited by CaddJax
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