Design intent – It’s a term many designers know and understand, but struggle to define. My favorite explanation is that design intent is how you want your model to behave when it is modified. Today’s demonstration from Doug Stainbrook explains inherent design intent within ordered models.
Here we have a history-based model, which has feature upon feature, and we can actually see how this model was created using the feature playback tool. First, the initial shape was formed with an extrude, then cutouts were added, and finally rounds were applied.
This has some inherent design intent in the way that the shape was created, but what if later we want to make modifications? In the video demonstration below (scroll to end of article to play), we will make the center post 10mm taller than the others and increase the width to 40mm. We will also change the overall thickness of the model to 100mm wide, while retaining the 35mm dimension and 29.74 degree angle on the front face. Remember, the design intent has changed. At the time that the part was created, it was important that the cutouts be the same width and the center posts be the same height, but that is no longer true with the modifications we make.
We will start by addressing the problem of the part’s overall width. We select the first protrusion from the feature tree, open its profile, and turn off the PMI. We can see that there are some dimensions for the sketches, and what we want to do is increase the width from 75mm to 100mm.
However, when we make that modification, notice the angle changed because the right side of the part moved rather than the left. To achieve our desired result, we will lock the 35mm dimension we wish to retain. Notice we cannot do that, however, as the part will be over-constrained. The 40mm dimension is locked, so we must unlock that before locking the 35mm dimension. Now we are free to increase the overall width to 100mm. However, when we do so, we see that both sides of the part moved symmetrically, which again is not our desired result. We must delete the inherent relationship that keeps the part centered on the base coordinate system before making our modification, and now we get the desired result we were after.
It’s important to pay attention to how the part was built and the relationships that were created, even if those relationships were unintended and simply happened to be created with the way the part was drawn.
That was a straight extrude. Now we will look at the cutouts.
Immediately we can easily identify an issue here: The cutout on the left does not go all the way through. Because we have a history-based model, Solid Edge remembers the depth of the previous cutout and establishes that as the depth again when we go to correct it. We can fix it by adjusting the cutout to go through in both directions.
The next thing we want to change is the widths of the cutouts, because again, it’s important that our center post be 40mm wide. We again turn off PMI and select the very first cutout to edit its profile. Change the dimension from 35mm to 30mm and add 5 mm to the other side.
We select the second cutout and repeat the process to make the center post 40mm wide. This requires a little bit of math to figure out, and we aren’t concerned with the width of the cutouts, which is what the original designer cared about when this part was made.
The final change we will make is to increase the height of the center post. Let’s see how much easier this process is in Synchronous Technology. We reopen the part and move all features to Synchronous, where it doesn’t matter how the model was built. For instance, if we need to change a width, we simply select the dimension and edit it. The blue face that is highlighted will change when the modification is made. It’s very quick and easy.
The same method applies to width. We select the dimension, make it 40mm, and symmetry is maintained.
If we wanted to maintain the 35mm cutouts, we could lock the two dimensions to prevent them from being changed. With synchronous technology, we can change the design intent on the fly.
Now we’ll increase the height of that center post by clicking and dragging. Notice that it is coplanar with the other two faces, as they move together. We turn off the coplanar design intent and now can move this independently however we want. The ability to change design intent on the fly is really powerful functionality. It’s very quick and easy to make modifications however we want to change the model.
Synchronous Technology gives you flexibility with design intent to make modifications however you want.