Concept Modeling of Automotive Seat using Autodesk Alias

Title of project: concept modelling of automotive seat

Objective:To build automotive seat using visualisation from three quarter views.

Tools used:

Freeform blend tool, CV curves, line, skin, align tool, trim, project, intersect, extend, detach tool, and transform tools, fillet, rail command, Ms Draft, duplicate curve, trim convert, etc.

Introduction:

Introduction to surface continuities and its types

Continuity is the smoothness of the junction i.e., two mating curves. Continuity is the condition that the more smoothly the adjoining surfaces flow

Generally there are 4 types of surface continuities i.e., we can have surfaces coming in contact in 4 different ways.

They are:

1. G0-position (touching)
2. G1- tangent (angle)
3. G2-curvature (radius)
4. G3-acceleration (rate of change of curvature).
5. G0-position (touching) continuity:

This is less smooth type of joint with common end point. This position is the only condition to satisfy the joint.G0 is the point continuity when one curve touches the other and shares the same boundary

2. G1- tangent (angle):

One can’t have G1 continuity unless you have G0 continuity.it is also called as second order of continuity i.e., to faces meet along a common edge at a tangent plane they share a common angle. The best example for G1 continuity is a fillet.

3. G2-curvature (radius):

G2 adds another order that must match across our pair of curves. For G2 it must a tangent to the curve and have the same curvature a point where they touch I.e., the input geometry must now be curved s well so the input containing a straight line can’t make a G2 curvature.

4. G3-acceleration (rate of change of curvature):

G3 continuity includes the concept of acceleration of the curvature; the amount of change in the curvature over the length of the curve.G3 is looking for balance on the rate of curvature.

Description:

1. Open auto desk alias and choose class a surfacing.
2. Import the canvas image by going to file > import canvas image > always create new layer.
3. Assign the canvas to a specific layer.
4. As the canvas image is provided with only one viewing angle rest of the surfaces is constructed using visualization.
5. Start by easiest part of the automotive seat which is the head rest.
6. Create the head rest by simple curves and move curves to adjust the form of the head rest.
7. Using skin command create the surfaces of the head rest later we can apply fillets.
8. To create back support of the seat start by creating the back support cushioning surface by visualization of the seat.
9. Trace the outlines of the seat at a certain view and modify the curves as per the requirement and shape of the seat.
10. By seeing three quarter views of a car seat we can visualize better how the surfaces of the seat are flowing.
11. Make the surfaces flow continuous and ensure that the proportion of the automotive seat is as per the requirements.
12. Make sure that the complete automotive seat sits in the dimension box.
13. To make cushion pads of the automotive seat first create a hypothetical curve that matches from the side view.
14. Later it can be modified based on the requirement that matches the dimension box.
15. For better continuity some surface s must be aligned forcefully so that continuity is followed for entire flowing surfaces.
16. The modified curves can only achieved by visualization only; one must know how the surfaces are flowing in reality.
17. Complete the back support and by that the bottom part can be visualized.
18. Complete the entire profile of the seat using “skin” and “blend” command and using rail command bottom support and back support can be constructed easily by one generation and one rail curve.
19. After construction of the sharp model save the file and then start adding fillets to the sharp model.
20. Evaluate the surfaces and clean if any abnormalities in the model.

Conclusion:

The automotive seat is padded part in the car where some part cannot be visualized hence closing the volume is crucial in modelling the automotive seat. Blending the surfaces give the model a good appearance.