3D viewing of objects give an indication of how they look like in real life. Viewing a PCB in 3D gives a rough indication of the board density and the overall size of the assembled PCB. This tutorial briefly explains how to create the main body and pin of a DIP8/300 package. The libraries supplied by Visionics already has the relevant 3D information attached to them but in case the user would like to convert his 2D packages to 3D, the 3D library editing tools may be used.
Launch 3D Library Editor
The 3D editor can be launched by selecting the menus - Package Editor | Open Package for Editing - ( Enter DIP8/300 ) / Edit menu / 3D view
The 3D workspace is displayed with three perpendicular axes and a default board containing the outline of the DIP8/300 package as shown below.
The actual view of a DIP8/300 Package is as shown below.
A package similar to this figure has to be created using the 3D items. The creation of the 3D package would have been easy had it not been for the semicircular notch on the top of the package. There are two ways of doing it. One is to load a rectangular block and then place a semicircular bar at the location of the semicircular notch. However to make the 3D view more sophisticated it is possible to create the package as one composite figure using what is called a Polyshape. Since the tutorial aims to acquaint the user with all kinds of 3D items, the main body will be created as a collection of basic shapes and the pin will be created as a polyshape. You might want to create the whole package using polyshapes as an exercise.
The tutorial illustrates how to create the two fundamental parts of the 3D package
1. The main body – consisting of the rectangular bar and the semicircular notch
2. The pin of the package. Once a pin is created it can be duplicated using Repeat Graphic Item option tool.
3. Select the Function toolCreate 3D Graphic Item -> Select the Option tool Create Rectangular Bar.
4. The option tools With Bottom surface, With Top surface and With Side surface(s) may be enabled to get a solid 3D package.
5. Click anywhere in the workspace, a rectangular bar will be placed with the center of its base placed on the intersection of the 3 axes. The rectangular bar will appear highlighted to indicate that the present focus is on it. Relocation and stretching may be carried out here. By default the Function tool Relocate 3D item gets enabled.
The rectangular block has to be relocated and stretched to fit in the area 1-2-3-4 as shown in the picture. The height of the rectangular bar should be set to the height of the body of the DIP8/300 package ( this data is available in the datasheet). The height can be set in two ways.
a. Stretch the item to the required height.
b. Enter the height in the Property window of the Rectangular bar.
6. Relocate the bar. Relocation of the block may be achieved by placing a contact point. A contact point is by default placed on the intersection of the 3 axes. To move the axes to a desired point press SHIFT and click in the direction where it has to be placed.
7. After moving to the desired location press Finish Relocation(F6)
8. Change the height of the rectangular bar according to the value given in the datasheets
9. Stretch the bar to fit on the component outline
10. Create the circular patch in the package. Load a semi-cylindrical bar.
11. Elevate the body of the package (both the rectangular bar and the semi-cylindrical bar) by around 15/20 mils (.015”) above the board. This can be done by entering this value in the Properties Window (adjust the Z position).
Creation of pins
So far the creation of the package required only the basic geometric 3D items like rectangular bar, semicircular cylinder etc. Operation on these items is such that their basic shape is always preserved.
For egs. The item given below when stretched will maintain its aspect ratio, ie. it will have a proportionate increase in volume since it is a basic 3D item.
Consider the requirement for a 3D item which looks like
This is a composite figure which can be derived from the basic shapes. For egs, a circular cylinder can be loaded on the workspace and it’s angular snap if changed to 30 degree (using it’s Property window) will turn the circular cylinder to a bar with 12 vertices. Now if one edge of this bar is pulled away from the center the composite shape shown in the figure can be obtained. In order to cater to situations where such figures are needed, Library Editor defines a general term called POLYSHAPE. A polyshape is a 3D item which has been derived from a basic 3D item and whose edges and vertices can be stretched (unlike those of 3D basic items).
The pins of a DIP package are composite figures. Using 3D Library tools, a pin which is shown below can be created.
Note: The pin dimensions are exaggerated values
This can be derived from a semi-circular strip by stretching its vertices and edges.
1.Load a semi-cylindrical strip on the workspace and move it to a distance away from the other items -> Finish Relocation
2.Set the height of the strip to around 0.055”. This will be length of sides bc / ad etc.
3.Set the number of vertices to 8.
4. Angle B = 90
5. Z Rotation = 90
6. X Rotation = 90
Now the item will look like
7.Once all the settings are made, the semi-cylinder can now be turned into a polyshape so that its edges and vertices can be stretched.
8. Select the Function tool Convert 3D item to Polyshape and click on the semi-cylindrical strip.
9. Creation of face “abcd”
10. Refer the picture of the pin. The length of ‘ab’ is .025”. As a rule of thumb, selection of edges is easier in Perspective View and setting dimensions in 2D views, like From South. Select Stretch item and select the first edge. Now select tab Edit Views in the 3D-view control and select From South. Now move the vertex such that it coincides with the adjacent vertex.
11. After the two coincide, select a Snap value of “ab” ie. .025”, press Shift key and click in the positive x-axis. Press Finish stretch. The face “abcd” of the pin is formed.
12. Creation of face “efgh”
Select the edge “gh” in Perspective Default View in 3D View Control and then move to the Edit Views -> From South view. First merge the two edges and then select a snap of 0.065” (the distance separating the edges ef and gh) and click on the negative z axis to complete creation of the face “efgh”.
13. Creation of face “ghij” and “ijkl” Select the edge “ij” and merge it with edge “gh” using the same method mentioned in the above steps. Now select a Snap value of 0.065” (distance separating the edges ij and gh) and click in the negative z axis.
Repeat the same procedure for the face “ijkl”.
14. As shown in the picture, the length of “ij” is lesser than that of the other edges (0.018”). To set this move to the Perspective Default View in 3D View Control and select the vertex i. Now stretch it along the y axis to a desired position. Press Finish Stretch. Repeat the same procedure with the vertices k and l.
15. Now repeat the pins for the rest of the package and place them in the pad holes in the 3D board of the editor to complete the 3d package of DIP8/300.