Something has gone awry, I don't know what or how


#28

I thought it was going to work for the whole process but for some reason I am getting an error even though all parts of the drawing were the same during design prior to push/pull.

image

Think I may have pushed it too high in this case on one part.

Fixed that but still a problem:


#29

Yes, you need a face for FollowMe tool, technically, still no solid (a face has only two dimension).

When you have a face that is isolated (no connecting edges or faces) it is pretty clear that a pushpull would create a solid based on that face, but when you have (multiple) offset perimeters, the algoritme to determine how the inside and outside are interpreted need a little help from the user.


#30

Thanks Mike.

Can’t understand why this part is giving me such problems:

Drill Press Table.skp (549.3 KB)


#31

I can’t see what is different about that corner compared to the other three:

Even when I can get it to follow the curve completely, it ends up with lines unlike the others.


#32

Generally, this means that the path which FollowMe was tracing had an “arc” which had been exploded (for whatever reason) into its individual edge segments prior to invoking FollowMe. When FollowMe encounters the vertex between two edges that are not welded together into a curve or arc or circle, FollowMe marks the new edges that are generated (to create the adjacent faces) as not-soft and not-smooth. Conversely, when FollowMe encounters a path vertex where the two adjoining edges are part of the same curve/arc/circle, FollowMe marks the new edges that are generated (to create the adjacent faces) as soft and smooth.

This is similar behavior to how Push-Pull behaves when operating on a polygon vs. a circle, for example.


#33

Upload the 3D model of your table.

I’m trying to understand how you are planning to use this on your drill press. Are you showing the top surface or the underside? A typical cast table would have ribs where you have channels and through slots on the diagonals.

If you’d told us a week ago that you wanted a 3D model of this table, I would have suggested that you draw 1/4 of the table as 3D before adding the slots, holes, channels, etc. And then rotate/copy as you did for the 2D version. It is usually much easier to start out thinking in 3D and then add the details than it is to spend a lot of time thinking only in 2D as in your example.


#34

Thanks for your replies.

I want to see it in 3d so that I can visualise how a drill press table will connect to it and it’s also a good excuse to practice using SketchUp. It’s better to record dimensions this way for me in all three axis as well.

I’m a bit puzzled at the moment trying to understand why sometimes SketchUp puts lots of lines on circles when they are pushed and it looks like my model is a bit of a mess as a result. I don’t know why they would have been exploded when I have not instructed this to happen.

If you could please have a look I would be grateful.Drill Press Table.skp (542.1 KB)

I have drawn the top and bottom and plan to combine them after I have extruded the bottom as in the file attached.


#35

So as I said, it would be better if you start out thinking in 3D instead of 2D. When you start out like you are doing a 2D drawing as you would on paper or some 2D CAD program, you make things difficult because you are adding details at the wrong time. As with the2D version I showed you last week, since the table is symmetrical in both the X and Y directions, you can save yourself a lot of work by modeling only one quarter of it. Note: I did my best to decipher what your drill press table looks like based on your model but I redrew it from the beginning.

From the back left:

  1. The raised edge of the table is easier to draw using Follow Me so I drew a path and a profile.
  2. After Follow Me.
  3. Now that there’s a 3D shape to work on, layout the details. Since the slots and central hole go through, there’s really no need to lay them out separately.
  4. Push/Pull opens the slot and the central hole.
  5. Add the ribs and the post.
  6. Rotate/Copy to make the other three quarters. Erase the coplanar edges, soften any other edges, and make it a component.


#36

Hello Dave, it’s clear that you are very skilled and I always appreciate your input.

It took me a long time to put the design I showed you together because of all the measurements. To start again in this way would take me a very long time.

I know in the long run it would benefit me because practising the concept you have explained would be beneficial.

For the purposes of this example, is there not a way to fix the problems I have with the circles without starting again?


#37

You can soften the edges on the cylinder but the rest of your model has enough problems that fixing it will probably be more work than starting from scratch. I guess it’s up to you, though. If you orbit around to look at the other side of the table you’ll see you are missing what would be the top face of the table.

At the very least you could draw the outside shape of the table and make that 3D and then copy the lines from your layout onto it.

What I showed is all very basic modeling using only the most fundamental tools. It’s straightforward, efficient and results in an accurate model assuming the dimensions you have are correct.


#38

In case you couldn’t tell, I did actually follow your instructions and built one quarter before duplicating it and removing the splits in the model that I shared. At that point it was fine and there weren’t any problems.

I find it very frustrating how easy it is to mess up a model and then even more so trying to fix problems, which sometimes is impossible.

I am going to try again the way you have shown. What I can’t tell from your image is how you got the shape right around the outside with the rounded corner in design 1 without drawing it as a square first etc.


#39

A big thing with the modeling is getting the right order of operations right. As I’ve said, with a 3D model, it’s best to start thinking in 3D instead of thinking in 2D and changing horses mid-stream. Your process of starting with a 2D face and dividing it with all those edges is the basis of your troubles.

I drew a path with an arc at the corner and the cross section of the table. Then used Follow Me to create the shape. Basically in one step that part is done.


#40

Thanks Dave.

Trying your way, I can’t get past the first step at the moment. When I click on the path of follow me, it comes up in a square and then if I click on the shape it does nothing:


#41

Explode the path component before running Follow Me.


#42

Okay, done. Not sure that the result looks right up close though.

Drill Press Table.skp (395.8 KB)


#43

There are missing faces there due to very short edges in the curve.


How did you draw that curve? It couldn’t have been as just an arc using the Arc tool. Here’s my arc drawn with 24 segments using just the Arc tool.

Sort out drawing the arc–it shouldn’t be divided anywhere like yours is–and it should all work just
fine.


#44

Thanks Dave.

It was a copy of the original curve which was drawn in the way you originally instructed so I don’t understand why that would become a problem now.

I ended up drawing guidelines like you to set the edges of the curve and the rotational point and redrew it as you said.

Out of interest, should a drawing always be white on top? If so, why isn’t it to start with like in your example? I presume this is why you reversed the faces?


#45

Also, following your new instructions, how do I deal with slopes?

The cross and pole have slopes on them.

Even though I drew lines through the existing slope at the sides, when I pulled the cross it left a gap (unlike in your example).

The geometry is very complicated at this point for making sure there are no gaps.

I don’t have any idea how to make the slopes at the side of the cross hit all parts of the pole as it goes further away from the cross or how to get a seamless slope around the pole going around the cross parts.


#46

The “slopes” you are talking about I assume are draft angles, and in the case of the cylinder might also be called a tapering cylinder. (a cone).

In that case my advice is to draw each part as a separate solid component, then use the solid tools and boolean operations to combine them into the final part.

Depending on what you are doing with this model, it might not even be necessary to combine them, like if you are using this purely for rendering or to check fit with a different virtual part cad model or something.

Another option, for the ribs is to just grab the two points at the top of the rib and drag them outward to the edge of the rim slope. For the central cylinder it is more complicated.


#47

No. Not the draft angle.

The slopes on the tops of the the ribs.

I made the quarter of the table a component making sure it shows as solid in Entity Info and then drew the ribs outside of the component making sure they extend into the central collar for the post. I started by drawing a face.

Push/Pull to give it thickness and copy the geometry to the other side…

Then with both of the ribs selected, I made a component and made sure it shows as solid. I made the ribs a component although later I will explode it. If I screw something up after exploding the component, I’ll still have the component in the In Model components so I don’t have to start over completely.

I used the Trim tool from Eneroth Solid Tools to trim the ribs to the center collar.

Then I exploded the rib component and while the geometry was still selected, I cut it to the clipboard (Ctrl+X). Next I opened the quarter table component for editing and used Paste in place to paste the rib geometry into the component.

Finally, erase any coplanar edges and make sure there are no internal faces or stray edges. The quarter table should be shown as solid in Entity Info when finished.