Once again we eavesdrop on our intrepid designers, Sol and Sal.
“Hey, Sal,” says Sol, “take a look at this.”
“You mean Figure 1, above?”
“Yes, that’s right. Tell me two things that are wrong with that part model.”
“Oh, that’s easy!” exclaims Sal. “It won’t work, and it’s ugly!”
“Sheesh, everyone’s a comedian,” sighs Sol, “but seriously – what jumps out at you?”
“I don’t know – it looks OK to me.”
“Okay, let me ask you this – what would happen if I changed the size of the chamfer on the right?”
“Let’s see,” said Sal, “oh, I see you’ve dimensioned that boss feature from that edge! So, if you changed the size of that chamfer, and that edge moved…so would the feature.”
“Exactly! Is that the design intent of the part?” asks Sol.
“I don’t know. But the more I think about it, probably not.”
“So what should have happened?”
“If that had been dimensioned to the back edge of the part instead, that feature dependency never would have been created.”
“Very good” says Sol. “And this is where I also recommend dimensioning sometimes in your isometric view, else you may have just grabbed the other edge of the same chamfer instead of the edge behind it.”
“Yes, you told me that” said Sal. “Okay, I’m with you…but where’s the other problem?”
“Click on that hole and hit the Edit Sketch icon. Tell me what you see.”
“Why, I see…Figure 2!” said Sal. “Hey, wait a minute…isn’t that the Coincident glyph? You must have let that point snap to the center of the fillet.”
“And so now if the fillet radius changes, that hole will move! But…that might be the design intent in this case.”
“Exactly,” said Sol, “and that’s the point, and the true power of parametric behavior in SolidWorks – we’re not just making something that looks like the part, we’re making something that behaves like the part!”
“Good advice” admits Sal. “But I still see other problems with the part.”
“What?” exclaims Sol.
“It won’t work, and it’s ugly!”