Jump to content

Another Complicated Arc Question


Recommended Posts

Hi, can someone tell me please how to draw arcs with below conditions?

 

1. There are arcs with radius of 2700 tangent to the blue circle and tangent to the arc with radius of 2100 which its tangent point is lies anywhere at red line.

2. The center point of the R2700 arc is above the red line and the center point of the R2100 arc is below the red line.

 

Please show me the construction geometry.

 

See the attached image for more detail please.

 

Thank you

 

Arc_Tangent.thumb.PNG.df37ccb45626f973b155cc3db293ed9b.PNG

Link to comment
Share on other sites

There is no information about where to start either arc or where to end them.

 

Use the Tangent/Tangent/Radius option to draw construction circles.

 

Where are these exercises coming from??

Link to comment
Share on other sites

OK, this is the picture of the arcs looks like.

How do you draw the R2690 arc that tangent to R30 circle at point A, and tangent to R2100 arc at point B, and the R2100 arc is tangent to 3° line?

Arc_R2100_(Edit).PNG

Link to comment
Share on other sites

I think you will have to use Parametric constraints.

You know, by offsetting the 30R circle, a circle on which the centre of the R2690 circle lies, and you know, by offsetting the 3° line, a line on which the centre of the R2100 lies. You know the distance between the two circles and you know the point of contraflexure (point B) is 90 from the base line.

Set up the constraints as needed and you will get the centres of the two circles.

I don't have parametric constraints on my version of AutoCAD, but as it came since AutoCAD 2010, you have all the tools to hand.

I have to do it by trial and error.

  • Like 1
Link to comment
Share on other sites

56 minutes ago, eldon said:

I think you will have to use Parametric constraints.

You know, by offsetting the 30R circle, a circle on which the centre of the R2690 circle lies, and you know, by offsetting the 3° line, a line on which the centre of the R2100 lies. You know the distance between the two circles and you know the point of contraflexure (point B) is 90 from the base line.

Set up the constraints as needed and you will get the centres of the two circles.

I don't have parametric constraints on my version of AutoCAD, but as it came since AutoCAD 2010, you have all the tools to hand.

I have to do it by trial and error.

 

Sorry, I would like to ask, how do you offset a circle? I know only how to offset a line.

Link to comment
Share on other sites

Have you tried yet with the same technique?

Your responses seem to show you have had no instruction with AutoCAD and are floundering. Is it really your metier?

 

  • Like 1
Link to comment
Share on other sites

22 minutes ago, eldon said:

Have you tried yet with the same technique?

 

 

Do you mean using the parametric constraints?

 

22 minutes ago, eldon said:

Your responses seem to show you have had no instruction with AutoCAD and are floundering. Is it really your metier?

 

 

I have basic foundation of AutoCAD as long as it uses classic commands. So parametric constraints would be my new experience in AutoCAD.

I will Google it of how to do the parametric constraints in AutoCAD 2014.

Edited by basty
Link to comment
Share on other sites

Here have you got with this? I think it would be easier for us to help in stages rather than walking you through the full solution - there is a lot in the second drawing you posted.

 

What have you drawn and what is the next step to do?

 

 

Link to comment
Share on other sites

There are several solutions to what you  ask.  For your construction keep in mnd the following:

  1. To find the center of a circle of a given radius that is tangent to a line create a line parallel to the line on both sides at a distance equal to the cicle's radius.
  2. To find the center of a circle of radius R1 that is tangent to a circle of radius R2 with a known location, create two circles concentric with R2.  The radii of these two circles are (R1 + R2) and (R1 - R2).
  3. To find the center of a circle that is tangent to a line AND tangent to a circle use the intersections of the lines and circles from the previous two constructions.

For your task create the white 2100 circle first. The center of the 2700 circle is at the intersection of a line passing through the 2100 and blues circles with either the 2670 or 2730 circles.

 

  image.thumb.png.1c6b780c798c10017e6b8abc51e2fd1d.png

 

Edited by lrm
  • Like 1
Link to comment
Share on other sites

15 hours ago, BIGAL said:

Why not post full image of task seen images like that before and they can be missing a vital clue. 

 

Because I rounded the number of the dimensions so that they are can be easy to read and remember/memorize.

Edited by basty
Link to comment
Share on other sites

You did not answer the request, that image appears to be one of those "exercise 23" draw this object and AGAIN often something is missing, post the full image.

Link to comment
Share on other sites

7 hours ago, BIGAL said:

You did not answer the request, that image appears to be one of those "exercise 23" draw this object and AGAIN often something is missing, post the full image.

 

Do you mean like this?

 

Full Image

 

What is "exercise 23"?

Full_Image.thumb.PNG.fcaed839678a718ab0d95458ee7ee6e2.PNG

Edited by basty
Link to comment
Share on other sites

Why is it constrained and no idea where to even start. Is this a real object for your company or a CAD Exercise out of a book etc.

Edited by BIGAL
Link to comment
Share on other sites

On 2/3/2024 at 5:34 AM, lrm said:

There are several solutions to what you  ask.  For your construction keep in mnd the following:

  1. To find the center of a circle of a given radius that is tangent to a line create a line parallel to the line on both sides at a distance equal to the cicle's radius.
  2. To find the center of a circle of radius R1 that is tangent to a circle of radius R2 with a known location, create two circles concentric with R2.  The radii of these two circles are (R1 + R2) and (R1 - R2).
  3. To find the center of a circle that is tangent to a line AND tangent to a circle use the intersections of the lines and circles from the previous two constructions.

For your task create the white 2100 circle first. The center of the 2700 circle is at the intersection of a line passing through the 2100 and blues circles with either the 2670 or 2730 circles.

 

  image.thumb.png.1c6b780c798c10017e6b8abc51e2fd1d.png

 

 

How do you obtain R2670, R2730, R2130, and R2070?

Link to comment
Share on other sites

50 minutes ago, basty said:

 

How do you obtain R2670, R2730, R2130, and R2070?

 

In your posted picture, I cannot see any circles that are of the size you have quoted.

 

@Irm's diagram does not show accurately your problem.

  • Like 1
Link to comment
Share on other sites

1 hour ago, basty said:

What do you mean? You should see the image that posted by lrm.

 

That is exactly what I did. @Irm 's diagram is not the same as your diagram.

 

So either you want to draw something like @Irm 's diagram, or you want to draw something like your diagram. If you want to draw something like your diagram, then solving @Irm 's diagram will not supply your answer.

 

For example, @Irm's diagram shows the r2100 arc tangential to the R30 arc. That simply does not happen in your diagram.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Unfortunately, your content contains terms that we do not allow. Please edit your content to remove the highlighted words below.
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...