Based Sketches, Closed Profiles and Self-Intersection

  • Thread starter mech-eng
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In summary, "closed profiles" refer to sketches that form a closed shape without any gaps or intersections. "Base sketches" and "base objects" are used as the foundation for creating 3D surfaces in a modeling software. These sketches must include closed profiles and cannot have any self-intersections. Self-intersection refers to when a line or curve crosses over itself, creating overlapping areas. In Solidworks, a simple line cannot be revolved around an axis because it is not a closed profile, but a closed shape such as a rectangle can be revolved.
  • #1
mech-eng
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Would you please explain what "closed profiles" mean and what self-intersection is?
"Both single and multiple sketches may be used as the base objects for this feature.Base sketches must include closed profiles and may not be self-intersecting."

Would you explain what "base sketches", "base objects", "closed profiles" and "self-intersection" mean in the link?
https://www.sharcnet.ca/Software/Ansys/17.0/en-us/help/wb_dm/dm_SufacesFromSketches3DMod.html

Thank you.
 
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  • #2
Open Closed.jpg
 
  • #3
Are the first one just a "closed profile" and the second "open profile"?

Thank you.
 
  • #4
This information is readily available if you use a google search. I did and here's what I found:

Self intersecting:

https://en.wikipedia.org/wiki/List_of_self-intersecting_polygons

Open vs closed profile:

https://forums.autodesk.com/t5/inventor-ideas/sketch-closed-profile-indicator/idi-p/6274511

When searching these kinds of topics it may be made more difficult because of the relative commonness of the words but if you persist and use image search too then you can often find what you're looking for. If after searching you still have some confusion then you can post what you've found and ask your question more confidently.
 
  • #5
If you are asking with the background being Solidworks then the first profile can be extruded. The second not and the third probably not.
 
  • #6
when we are dealing with sketches here, I also would like to ask why a simple line cannot be revolved around an axis? Let's think that line as a pencil. Put it horizontally and parallel to x-axis above the x-axis. Then if we start to turn it around the axis I think there should be a solidbody with space inside it. My instructor said I could not revolve a line but would revolve a closed sketch such as a rectangle.

Thank you.
 

1. What are based sketches?

Based sketches refer to drawings or sketches that are created using a base or reference point. This base can be a specific point, line, or shape that the rest of the sketch is built around. Based sketches are commonly used in technical drawings and design processes.

2. What is a closed profile in relation to sketching?

A closed profile in sketching refers to a shape or outline that has no open ends or gaps. This means that all lines in the sketch connect and there are no intersecting lines. Closed profiles are important in technical drawings as they represent complete and accurate shapes.

3. What is self-intersection in sketching?

In sketching, self-intersection refers to the point where a line or shape overlaps itself. This can create confusion and inaccuracies in the sketch, especially in technical drawings where precision is crucial. It is important to avoid self-intersection in sketches to ensure accuracy and clarity.

4. How do I prevent self-intersection in my sketches?

To prevent self-intersection in sketches, it is important to plan and carefully construct the sketch. Use a light hand and avoid drawing over the same line multiple times. It can also be helpful to use a ruler or other tools to create straight lines. Constantly checking and correcting any potential self-intersections can also help prevent them from appearing in the final sketch.

5. Can closed profiles have self-intersections?

No, closed profiles should not have self-intersections. If there are self-intersections within a closed profile, this can lead to inaccuracies and confusion in the sketch. It is important to ensure that all lines in a closed profile connect and there are no overlapping or intersecting lines.

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