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Conclusion

1.      What is the difference between a numeric and a geometric constraint?
Geometric constraints are constant, non-numerical relationships between the parts of a geometric figure. Numeric constraints are number values, or algebraic equations that are used to control the size or location of a geometric figure.

2.      What advantages are there to using parametric equations instead of numeric values?
Using parametric equations are quicker because after you’re done with the equation and need to reuse it, you can just type down the name of the parametric name ex: d1.

3.      What disadvantages are there to using parametric equations for numeric values?
If you don’t write down the equation correctly or if there’s a mistake, the equation wouldn’t be able to be used.

1.What 3-D CAD functions could be used to create a wire coat hanger?
The coil and the sweep function.

2.      What feature would be used to create a 3-D representation of a spindle that was created on a wood lathe?

I would use the revolve feature.

How does a 3-D CAD solid model program keep track of the changes that are made to an object?
They keep track of the changes on the bottom left browser.

4.      If a mistake is made, how does the user make a correction without using the undo function?

Go back and edit the sketch or feature by right clicking and selecting the edit sketch feature.

1.      What is the difference between area and volume?

Area the measure of the two - dimensional space enclosed in a shape while volume is the measure of the three – dimensional space in enclosed in a shape.

2. What is weight density?
Weight density is an object’s weight per unit volume.

3. How is an object’s mass different from its weight?
Mass is the quantity of matter in an object.  Weight is the force of gravity acting on an object.

4.      How does surface area differ from area?
Area the measure of the two - dimensional space enclosed in a shape.  Surface area is the sum of all the areas of the faces of a three dimensional

1.       What is a geometric constraint?

A Geometric constraint is a Constant, non-numerical relationship between the parts of a geometric figure.

2.       What are the different types of geometric constraints that are applied to sketches, and what are their functions?

Perpendicular is a constraint that causes lines or axes of curves to meet at right angles.

Parallel causes two or more lines or ellipse axes to be equidistant from each other.

Tangent is used to cause two arcs or a line and an arc to intersect at a single point perpendicular to the arc’s radius.

Coincident fixes two points together, or fixes a point to a curve.

Concentric causes two or more arcs, circles, or ellipses to share the same center point.

Colinear causes two lines or ellipse axes to lie along the same line.

Horizontal causes lines, ellipse axes, or pairs of points to lie parallel to the X axis of the sketch coordinate system.

Vertical causes lines, ellipse axes, or pairs of points to lie parallel to the y axis of the sketch coordinate system.

Equal forces line segments to be the same length and arcs or circles to have the same radius.

Fix constrains points or curves to a specific point on the sketch coordinate system.

Symmetry causes selected lines or curves to become symmetrically constrained about a selected line.

3.How is a geometric constraint different from a numeric constraint?

In a numeric constraint, a number value, or algebraic equation that is used to control the size or location of a geometric figure.In a geometric constraint, a non number value is used to control therelationship of the parts to the figure.

4.What types of numeric constraints may be applied to sketches? You can use the general dimension to dimension out your figure.
Auto dimension is used to dimension it out automatically.

With CAD, you can draw more accurately and is it easier to constrain it together so you won’t have to do a lot of erasing and you can see your model in many views.

Freehand drawing is sometimes easier because if you are doing a rough draft, you can go back erase it quickly and do it over. You wouldn’t need to worry about the size until you get your ideas down.

Why is placement of your dimensions so important?

The placement is important because if the wrong dimension is used, then the part might not fit properly.

What is the difference between size dimensions and location dimensions?

Size dimension is what its actual size is and location dimension is where the part goes.

Why do designers need to fully dimension a part?

Designers need to fully dimension a part so that the part will fit.

What does it mean when a sketch is over dimensioned?

When a sketch is over dimensioned, the sketch is too big for the actual size.

1.      Why are standardized units of measure important to scientists?
It is important so that the scientists wouldn’t get confused when measuring an item.

2.      Why are standardized units of measure important to engineering?
It is important to engineering because if they used the wrong units, someone else might forget to convert it into the standard units.

3.      Which unit of measurement is used the most in science and engineering around the world?
They usually use the system of the units (SI) to measure around the world.

1.         Why would building professionals, such as machinists and contractors, prefer multiview drawings over pictorial drawings?

Professionals prefer multiview drawings over pictorial drawings so that it’ll be easier for them to make the object. Since multiview shows how the object looks like on all the sides and pictorial drawing only shows it from one angle.

2.           How would you describe the geometric relationship that exists between the adjacent views of a multiview drawing?

They all share the same view of an object.

3.      Why is it important to layout a multiview sketch with points and construction lines before drawing object lines?

It is important so that you have an idea of where each line ends on each point. You can also fix your mistakes easier without it looking messy.

4.      What is the purpose of hidden lines and center lines?

Hidden lines are used to show interior detail that is not visible form the outside of the part. Center lines are used to define the center of arcs, circles, or symmetrical parts.

1.      What is a vanishing point?

A vanishing point is a point in a perspective drawing where parellel lines appear to converge.

2.      Aside from the number of vanishing points, what is the difference between a one-point, two-point, and three-point perspective sketch?

A one-point perspective looks more leveled to the eye. A two-point perspective makes the object appear downward, and a three-point perspective make the object appear more upward.

Oblique sketches 09/27/2007

1. Why practice sketching shapes when a Computer-Aided Design (CAD) program can produce much more accurate Geometry?
Practicing sketching shapes will help people get a get a visualization of what your item is going to look like. Then you can use your final drawing in the computer.

2. What pencil techniques are used to create the differences between construction lines and object lines?
A construction line is very light; it is used when you are first sketching out the object. Then you use the object lines, which are very dark; to define the shape you drew.

3. What are the differences between oblique sketches and isometric sketches?
Oblique sketches are more flat looking because you see it from the front view. Isometric sketches look more three-dimensional because you see it from the side view.

1.      What is the difference between a two-dimensional sketch and an isometric sketch?
A two dimensional sketch looks flat while an isometric sketch looks for three-dimensional.
2.      Why do designers use tonal shading on their sketches?
Designers use tonal shading to help make the drawing look more three-dimensional.

3.      If you were not given isometric graph paper, what technique could you use to approximate the proper isometric angles in order to complete an isometric sketch?
Draw a box that could fit the object inside and start drawing from there.

## Author

Hi. Just call me Chong. I am educated a St. Paul School.