This page is a tutorial on how to use the Astroid and the Astroid Spatial User Interface (Astroid SUI) with Inventor and contains the following sections.
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(Click on a heading to jump to it) New Items Learning To Crawl Placing the Spin Center Using Perspective Fencing the Spin Center Learning To Walk 2D Sketching and Drawings Straightening Views Learning To Run Staying Upright Learning To Fly |
- the Basic control mode - the Normal control mode - the Pan/Zoom control mode - the Camera control mode |
The Astroid add-in adds
The Astroid tab is placed after Inventor's View tab and appears in Inventor’s part, assembly and drawing environments.
In the ‘Basic’ control mode a small green overlay circle shows the spin center position during motion.
The Astroid⇒Buttons command brings up the Astroid Buttons dialog box to configure the Astroid buttons.
In perspective views there is a Perspective Speed value that is optionally displayed in the top left corner of the active view.
Begin by opening a part or assembly and select Astroid⇒Set Demo Settings. Lightly push and twist the Astroid ball to pan, zoom and spin the model. Notice how the spin center appears at the middle of the model when moving the ball. The center of the physical ball corresponds to the spin center. Pushing through the center of the ball causes the model to pan and zoom accordingly. Twisting about any axis passing through the center of the ball causes the model to spin about the spin center accordingly. Try to keep the spin center away from the edges of the view as the spin center is ‘fenced’ at the edges of the view. Take a few minutes to become comfortable using the ball. This is the Basic motion control mode as displayed in the Ribbon's Motion panel.
If you have any difficulty try turning on Astroid⇒Single Axis to allow only the main X, Y or Z push or twist to operate at any one time.
Run the command Astroid⇒Pick then pick somewhere on the model. This places the spin center at the picked point. Move the ball to see the spin center in its new position. Try zooming in, getting quite close to the spin center. By placing the spin center anywhere on the model notice how quick and easy it is to zoom in to any particular area and still be able to easily spin and view the model.
Position the mouse cursor so a mouse click won’t do anything, such as the toolbar background near the top right of Inventor's window. Press and hold the left mouse button then try panning the model. Notice how the spin center pans instead of the model. You can use this mode to position the spin center anywhere in model space, not just on a surface.
A CAD user's design workflow typically involves zooming in to a small region of the model, doing some creation, editing or querying, then zooming back out. The 3D model is generally spun a little during this activity. The power of the Astroid comes from the ability to quickly and easily zoom in to an area of interest, do some work then zoom back out as this workflow is repeated over and over. Once you are accustomed to this interaction you will find it very difficult to work without an Astroid.
Now turn on perspective using Inventor’s View⇒Orthographic/Perspective command. Notice how a new status window appears in the top left corner of the active view. This shows the Perspective Speed. In perspective views graphical items closer to the eyepoint move faster across the screen and items further away move slower, just like in the real world. The perspective speed determines how fast the view pan's and zooms in model space to deliver the same screen motion. In the Basic control mode the perspective speed scales with the distance of the spin center from the perspective eyepoint. It is this distance that matches the response of motion in orthographic views. For a given push the spin center will always pan with the same screen motion for any zoom and for either perspective or orthographic views.
Rotate the model so the spin center is on the far side of the model then pull the model toward you to zoom in. Keep going. This will pull the model over the eyepoint and allow you to see inside. Inventor doesn’t draw the back of surfaces so if the eyepoint is inside solid material then things may look a bit odd. With a little practice you will be able to view internal details by placing the spin center on them then zooming in. This adds a whole new dimension to working with Inventor.
A fencing setting, used only in the Basic control mode, will prevent the spin center from moving past the edges of the view. By default this setting is on. When off the spin center can be moved out of the view.
The Basic control mode is fine for some people and in certain circumstances. For general CAD work the Normal control mode saves time as it avoids the need to keep repositioning the spin center. In the Normal control mode the spin center is fixed at the center of the view and at a distance into the view. The area of interest needs to be positioned over the spin center before zooming in otherwise a small rotation will cause the model to fly off screen, apparently out of control. Spinning the model back and forth a little when zooming in causes you to intuitively push the area of interest to the center of the view and, in so doing, push the area of interest over the spin center. Try this in both orthographic and perspective views.
To change the area of interest from one area to another try aligning the two areas to be the same distance from the eyepoint then pan across so the new area of interest is at the center of the view then zoom in. This quickly positions the area of interest over the spin center.Also try using Astroid⇒Pick then pick a point and notice how the model pans to the spin center. In perspective views the perspective speed is also set to match the picked distance.
When working with a 2D sketch the sketch typically the sketch should only be panned and zoomed, not rotated. The Astroid⇒Pan/Zoom command to override the control mode setting and ignore rotation. The Pan/Zoom control mode actually is the Normal mode without spin. In perspective views use the Astroid⇒Faster, Slower or Pick commands to adjust the speed of movement as required.
The Pan/Zoom mode is the only mode in the drawing environment. It is straightforward to use.
Often a view like a top, front or isometric view is required that is either perfectly aligned with the axes or at an isometric orientation. The Astroid⇒Straighten command rotates the model about the spin center to the closest of the 48 possible orthogonal or isometric views. First rotate the model close to where you want it then use the Astroid⇒Straighten command.
Turn on perspective, use Astroid⇒Set Demo Settings then select the Normal control mode. Position the mouse cursor so a mouse click won’t do anything, such as on the toolbar background near the top right of Inventor's window. Press and hold the left mouse button then zoom in and out with the Astroid. Notice how the perspective speed doesn’t change. Try to zoom in and keep pulling the model right past the eyepoint so, in one sense, the virtual camera flies right through the model. In the Normal control mode the left mouse button momentarily inverts the Astroid⇒Auto setting.
Zooming right in close in the Normal control mode will bring the spin center right up to the eyepoint where the perspective speed approaches zero and motion appears to hit a brick wall. Using the left mouse button or turning the Astroid⇒Auto setting off automatic adjustment off permits the model to move right past the eyepoint. With some practice it is possible to fly through the model to create an impressive demo.
Most models have an 'up' direction that preferably should remain upright and not tilt to one side. For instance, when walking (or flying) through a building it is preferable to keep the camera upright is the case in the real world. The Astroid⇒Keep Upright flag enables this feature and the Up Direction setting determines which axis is ‘up’. Turn on Keep Upright and notice how the specified axis of Inventor’s triad in the lower left of the view (when enabled) is always drawn on a vertical column of pixels.
In the Camera control mode the spin center is located at the perspective eyepoint. This is similar to a common mode in first person shooter (FPS) games but the Astroid provides the full six degrees of freedom. This power can take some time to master. Many users are content with just the Basic and Normal control modes.
With the spin center at the perspective eyepoint the perspective speed cannot be automatically adjusted. Consider, for example, a view with a coffee cup nearby and a mountain in the distance. Should forward movement move slowly towards the coffee cup or rapidly towards the mountain? The perspective speed setting needs to be radically different for each case. Use the Astroid⇒Faster and Slower commands to double and halve the perspective speed setting. Use Astroid⇒Pick and pick a point to set the perspective speed to match the picked distance.
If you expect the ball to be moving the virtual camera through model space instead of moving the model then turn on the Astroid⇒Reverse Directions flag. This reverses the Camera control mode's motion.