History Based Direct Modeling Using IRONCAD – Part 4Featured, Reviews Friday, October 15th, 2010
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In this part of the series I would like to draw a comparison between how direct modeling in done in IRONCAD and Solid Edge ST3. In ST3 if you have an ordered feature tree and wish to push and pull faces around across multiple features to effect a design change, you need to move the features over to the synchronous side and then thrash the model around. The important thing to note here is that this is a manual process. Solid Edge does not move the features for you. As I explained in my series on ST3, you also need to do this thoughtfully because you need to know exactly which features you need to move because once they are on the synchronous side you cannot bring them back. They get dissolved into the base body as synchronous features and are not ordered features any more. And last but, not the least, in ST3 moving an ordered feature to the synchronous side ends up moving all the features above it. And that is a big pain because if the model was not designed “properly” you can end up moving features that had nothing to do with the change you are trying to make. And again, if you want to prevent that from happening then you need to manually reorder the features in the tree so that you can have them remain on the ordered side of the feature tree.
So as you can see, synchronous technology in its present form can be a bit cumbersome for the user. True, it does split up the feature tree into two (or three) parts which can be managed differently. But the user is still left to figure out exactly where he needs to split the feature tree and/or how he needs to reorder the features if the need arises. So at the end of the day, the user still has to bother himself with the feature tree.
And this is where I believe IRONCAD beats Solid Edge ST3 hands down. In IRONCAD, if you wish to move a few faces you simply pick them and move them. You don’t have to go to the feature tree and figure out which features these faces belong to. And then push down the features between them so that they are not dissolved into the base body. IRONCAD does that for you. So I could pick two faces, one belonging to the first feature in the tree and the other belonging to the last feature and move them how I wish. The software will dissolve only the first and last features and leave everything else intact.
Let me show you this with a simple example. Say I have three block features one stacked above the other. I create the bottom block first, then the middle and finally the top. Suppose I want to move the faces of the bottom and top blocks and leave the middle block intact, IRONCAD lets me do that without having to bother myself with the feature tree. Take a look at this video.
IRONCAD let me know exactly which features would need to be combined into a Brep (dumb solid). It also reminded me that henceforth I would not be able to edit those features as IntelliShapes because obviously their IntellliShape information would be lost due to the combine. However, as you can see in the video, I still can move the faces of the Brep around using the move face and similar commands. Also as you can see, the middle block lay intact as an IntelliShape and I could edit it using its handles. As far as the feature tree goes, in this case, IRONCAD combined the bottom and top blocks into a single Brep and put it at the top of the tree and placed the middle block feature after it.
Lets see how this works in a real world part. Take a look at this video. First I pick on two different features, a slot and a hole, to show that they are not part of a single Brep. Rather they exist as two separate features in the feature tree. Then I pick faces on both of them and move them using the TriBall, IRONCAD’s direct modeling gizmo. The software warns me that the direct modeling operation I am trying will combine both the features into a single Brep, which is does.
As you can see, even after combining the features into a Brep, I could still edit it using its handles. For closer control I could pick individual faces and move them as well.
But the absolutely amazing thing is that I don’t even know where these two features lie in the feature tree. Which one is before the other and whether both of them lie before or after the extrusion feature that they sit it. Frankly, I don’t care. I know that IRONCAD will figure that out for me, which it did. All I simply did was pick the faces I wanted to move and moved them. IRONCAD took care of the rest. As simple as that.
Part 5 >>