How to Draw this Curve?

[basty]

Does anyone know how to draw this curve exactly similar like the picture in AutoCAD only by reference (in this case is a picture) by using Spline command.

 

Thank you

 

[BIGAL]

Ellipse ?

 

Looks like a Nurb curve, add more points to a pline then fit or spline.

[basty]

Why do you say ellipse? It doesn't look like an ellipse to me. Or maybe you're telling me something that I don't know yet. Please explain why do you say ellipse.

What is pline? What is the difference between pline and  spline?

Edited July 5, 2023 by basty

[SLW210]

I moved your post to the AutoCAD 2D Drafting, Object Properties & Interface Forum, please post in the correct forum.

[lrm]

There are several curves in the picture.  Which curve are you trying to create? I assume that you want the curve in 3D. Yes? If so, you will need more information.  For example, at least two orthographic views showing the curve.

[CyberAngel]

If I had to reproduce a set of curves like that from a picture, I'd attach the image as an external reference. That way I could place my control points and adjust them in real time, instead of having to export, check, adjust, repeat.

 

With 3D, of course, you're talking about another layer of complexity. As BigAl says, you may want a NURBS curve. Which is really just a fancy spline.

[basty]

1 hour ago, lrm said:

There are several curves in the picture.  Which curve are you trying to create? I assume that you want the curve in 3D. Yes? If so, you will need more information.  For example, at least two orthographic views showing the curve.

 

I need to draw all of them, start from A and end to B (please see attached image). Or you can start from B and end to A. If you can't provide me answer with all curves shown in the image, just show me how to construct/draw the inner curve. For now, I just need it in 2D. I don't know what 3D curve is but yes I would like to know how to draw/construct 3D curve you had meant after I get to know how to draw/construct the curve in 2D.

Edited July 5, 2023 by basty

[lrm]

Start by placing a copy of the image into AutoCAD and scale it to the correct size and lock its layer.

Using the spline command create a curve using the fit points method.  In general you should use as few fit points as possible and you may need more fit point where the curvature has a smaller radius.  Here's my first attempt.  Not the location of the fit points.

The curve needs some editing in this area.

You may not be able to get the desired curve by just moving fit points.  For example:

Select the spline and pick the Control Vertices method for editing

Experiment with moving the CVs.

If you need more local editing of the curve use the SPLINEDIT command to add additional CVs.

 

[basty]

There are 18 points available. How do you know there are 18 points and how do you know the position of these points? If you change the position of these 18 points then the curve shape will be different. Is it by trial and error method?

[lrm]

I eyeballed the location of the fit points and the spacing was done a bit by experience.  Yes, there's some trial and error involved.

[basty]

OK. Thank you very much for your help lrm.

Edited July 5, 2023 by basty

[basty]

Does anyone know why BIGAL says Ellipse in his post?

[BIGAL]

That was just a start guess as an ellispe is a complex curve and may be ok for the left side, it would be a start as you may need more than 1 ellipse you can break and trim then add fillets.

 

As its a very complex shape using the spline option is the way to go. As mentioned more or less control points help in making the shape. Car stuff is based on NURBS high end software. 

[alex marfi]

Drawing a curve depends on the specific shape and context you're referring to. There are various ways to draw curves, and the method you use depends on whether you're drawing by hand or using software. Here's a general guide:

**Drawing a Curve by Hand:**
1. Start with a pencil and paper.
2. Decide on the type of curve you want to draw, such as a simple arc or a more complex curve.
3. Visualize the curve you want to create.
4. Begin drawing the curve with light, gentle strokes, making adjustments as needed.
5. Use an eraser to correct any mistakes or refine the curve as you go.
6. If precision is essential, consider using a compass or a French curve to create a more accurate curve.

**Drawing a Curve in Software (e.g., Using a Vector Graphics Tool like Adobe Illustrator):**
1. Open your vector graphics software.
2. Use the Pen Tool or Bezier Tool to create anchor points that define the curve's shape.
3. Click to create anchor points, and then adjust the direction handles to control the curve's shape.
4. Continue adding and adjusting anchor points until you've drawn the desired curve.
5. Use tools like the Convert Anchor Point Tool to refine the curve as needed.
6. Once you're satisfied with the curve, you can fill it with color, if desired.

To provide more specific guidance on drawing a particular curve, please provide additional details about the shape or context you're referring to.

Edited October 29, 2023 by CADTutor
Link removed

[bgmi41075]

maybe you're telling me something that I don't know yet. Please explain why do you say ellipse.

What is pline? What is the difference between pline and  spline?

[ReMark]

Pline = Polyline.  Spline = is a smooth curve that passes through or near a set of fit points, or that is defined by the vertices in a control frame.  An ellipse is a curve surrounding two focal points.  The shape of an ellipse is determined by two of its axis, which defines the length and width.  All of this information is readily available on the Internet.

[basty]

What is polyline?

[lrm]

An AutoCAD polyline typically refers to a 2D object that is composed of a series of segments.  Each segment may be either a straight line or an arc.  A polyline may be an open or closed shape. Although 2D, it may lie on a plane at any orientation in 3D space.