I created a drawing of a rail with a slider on it. I created the slider as a solid and then put four holes in it using boolean diff. Everything looked fine so I saved the drawing. I now realize that the holes are wrong. If they needed to be bigger, I would just use another diff operation, but they need to be smaller. I wish I could just "undo" the operations and make the holes disappear, but since I've done a save, I can't. Is there a way remove or "fill in" the holes so I can start over without having to recreate the slider from scratch? I've included the drawing so you can see what I'm talking about.
Thanks,
Mark

For erase a the holes
Select the inner surfaces, erase them, then erase circle top, and circle down on the surface
You have erase the vertical hole ;)

PS
Take the habit to draw at the same scale than the grid, it's very difficult to manipulate something flying on the faraway free 3D space ;)

Little trick of selection
Select one inner face, you can now make a rectangle box selection, left to right for select all faces inside the box selection : erase them
then make the same with a circle, you can now make a rectangle box selection, left to right for select all circles inside the box selection, erase them
That all maybe 2 seconds

I am unable to select the inner surfaces. Whenever I try, it just selects the whole solid. What do I do now?

Just double click on an inner face, or click one time and reclick one time on an inner face!
Then use a selection Box left to the right!

For the under

I did solve my problem finally, with your help, but I wasn't able to get "loft" to work that way for me. I ended up drawing rectangles over the open areas, using "planar" to make them surfaces, and then "union" to use them to seal up the holes. I could then cut the new holes using "diff".

BTW, the part looks great now but I wonder if the database for it is a mess because of all the operations that I've had to go through to get where I'm finally at.

Thanks,
Mark

MoI doesn't have a database as such. Your model is what it is now. MoI's not history based like Solidworks.

You have history for some functions, but you must keep curves generators and don't modify the object with other functions!
Example: a sweep will be modify till the end of the session but it must stay independent !

Hi Mark,

> I am unable to select the inner surfaces. Whenever
> I try, it just selects the whole solid. What do I do now?

You need to "drill in" to select a face instead of an edge - that's done by doing a second click on the same object.

When you do 1 click on an object, the entire object is selected, but if you then click on it a second time selection will change to a sub-object (a face or an edge).

Edges will take precedence over faces, so in order to drill in to a face you may need to zoom in a ways until the face is a bit larger on the screen so that you have a good spot where you can click on it that is not close to an edge.

Then like Pilou says once you have deleted those inner side wall pieces you can then select the edges on the outside piece which are now no longer attached to anything and also delete those, that's called an "untrim" operation.

Here is a post that describes untrimming in some more detail with an example on a box:
http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4

Also here is a more complex mini tutorial that talks about using untrimming and re-trimming to repair an object that had a boolean done to it in an incorrect location:
http://www.moi3d.com/forum/index.php?webtag=MOI&msg=446.17


It is also possible to model a covering piece and use a boolean or join to fill something in as well, but it can be easier to use the untrim method when the hole is a kind of isolated thing right in the middle of the base surface.

- Michael

Hi Mark, here's a video showing how to use untrimming to remove a hole in your particular model:



So a couple of things to note there - first of all notice how I've zoomed in a ways so that the side wall pieces that you want to remove are not too small on the screen? That's important so that you select them more easily.

Then I do one click to select the full object. After that initial click, when I move the mouse around you can see that faces and edges are highlighting - those highlights are showing you want sub-object will get selected if you do a second click to drill-in.

Then I do the second click to drill in to one of the side wall faces, then I do a window selection to grab all the other side wall faces (once you have selected 1 face or 1 edge, then window selection will target faces or edges of that object after that).

Then they are removed by pushing the Delete key, that leaves a hole on the top face that is not attached to anything else, and holes like that can also be removed by delete, so I drill in again to select that top edge and use Delete again to remove it - the result is the full top surface is recovered.

- Michael