Drawing Isometric to Scale

[Boro Nut]

I don't do many isometrics, but when I do they invariably need at least some elements to be set out to scale, if only to keep a realistic sense of proportion. My normal method of working in ortho projection is to draw grid lines and offset them by the required amount to establish the shape of the object, and then either trim them to size or draw lines between the established intersection points.

 

But the offset command still seems to work in ortho mode (horiz or vert) even though my drafting settings are set to iso, so the offset distance between two points in isometric projection is not correct. My workaround is to draw circles of specified radius to determine where these intersection points need to be.

 

Is there a way of offsetting elements in the chosen isometric plane? Failing that, what is the quickest way of switching between rectangular and iso snap?

 

Boro Nut

[wannabe]

One of the buttons, tab or one of the F buttons, changes the plane. That should save you from switching between iso and rec. snap.

[ReMark]

Having encountered the same problem in the past I switched from drawing my "iso" in 2D to 3D and all my problems went away. I draw my isometric full size in model space then switch to my layout, insert a viewport (set my view to SE isometric) and scale it up/down depending on my needs.

[Boro Nut]

One of the buttons, tab or one of the F buttons, changes the plane. That should save you from switching between iso and rec. snap.

F5 cycles through the iso planes but they forgot to also include ortho.

 

I may have a dabble at 3D.

[rkent]

I don't do many isometrics, but when I do they invariably need at least some elements to be set out to scale, if only to keep a realistic sense of proportion. My normal method of working in ortho projection is to draw grid lines and offset them by the required amount to establish the shape of the object, and then either trim them to size or draw lines between the established intersection points.

 

But the offset command still seems to work in ortho mode (horiz or vert) even though my drafting settings are set to iso, so the offset distance between two points in isometric projection is not correct. My workaround is to draw circles of specified radius to determine where these intersection points need to be.

 

Is there a way of offsetting elements in the chosen isometric plane? Failing that, what is the quickest way of switching between rectangular and iso snap?

 

Boro Nut

 

Strictly speaking you are doing Isometric Drawing and not Isometric Projection. As you found out, offset won't work, you will need to copy

instead.

You can change between standard and isometric modes by putting something like this in the ACADDOC.LSP. Then you type SI or SS to toggle between the two.

Set the 0.01 and 0.125 to what ever value you like to use for snap.

(DEFUN C:SI () (SETVAR "CMDECHO" 0)(COMMAND "_SNAP" "STYLE" "ISOMETRIC" "0.01")(PRIN1))

(DEFUN C:SS () (SETVAR "CMDECHO" 0)(COMMAND "_SNAP" "STYLE" "STANDARD" "0.125")(PRIN1))

[mugshot]

... if you are in an isometric plane and offset an object, you'll get nuts, i prefer you should copy and input for the distance. you will have a better spacing than offsetting.

[ReMark]

But if you draw your isometric in 3D and change your UCS you can offset til the cows come home with no problem.

[rkent]

But if you draw your isometric in 3D and change your UCS you can offset til the cows come home with no problem.

 

I agree with going 3D but I like trying to answer the OP's question.

[ReMark]

Didn't mean to step on your toes. Mea culpa. Please continue.......

[rkent]

I can tell from your post that you took my response the wrong way and for that I apologize. Wasn't meant to be confrontational or snide, just explainin' myself.

[ReMark]

On the contrary. Your statement was exactly on point. I was taking the thread off topic. No offense taken and no apology required on your part. We're cool.

[Boro Nut]

... if you are in an isometric plane and offset an object, you'll get nuts, i prefer you should copy and input for the distance. you will have a better spacing than offsetting.

I can't see how that would work. If I am trying to set out some column centres say at true scale, the true dimension is in the inclined plane, so I would have to calculate both the X and Y components in order to copy it to the right place. That's more work than drawing a temporary circle of the necessary radius and copying the elements to that temporary intersection point.

 

After a bit of dabbling it seems to me the only way to make use of offset is to use it in ortho mode to establish the intersection point on the basis that the Y component will always be half of of the inclinded dimension you are trying to determine (Sin30=0.5). So having drawn an inclined line of indeterminate length from a datum point on the elements you want to offset, you can establish the required intersection point on it by drawing a horizontal line from the same base point and offsetting it vertically by exactly half of the inclined distance that you want to offset by. The intersection with the inclined line indicates where you need to copy the elements to. As you need to change back and forward between ortho and iso snap I'm not convinced this is any quicker than drawing the temporary circle.

 

Boro Nut