Hello.
Without an image, many users may feel reluctant to get involved.
I'm no expert, but, maybe questions below can help you self-diagnose the problem you're experiencing. Maybe others know best which questions to ask you.
So...
First, the only relevant thing I can see to your situation is when I have a solid from joined surfaces, I try to create plates or floors "inside it", and the floor instead shows several pieces outside, not one piece inside. It sounds like you may need to shell the solid before creating geometry inside of it.
If that doesn't apply, maybe go through the following (for sanity checking or for familiarization):
About the thing you're trying to modifY...
— Is it a sphere/cube made as a surface, or is it a solid?
— If it's a solid, is it shelled or is it non-shelled?
The geometry you're using as the modifiER...
— is it a surface, a solid, or a set of curves? A tube?
Is the geometry natively constructed within ViaCAD, or imported from another app?
Are you trying any Boolean tools, or, say, using a surface to do anything. Is your install of the app letting you Boolean add/subtract/etc two spheres?
If it's a solid, try the Push-Pull tool or other available Modify tools in the menu or tool pallet.
As for surfaces, make a surface. Then, copy the surface and immediately paste back the surface. Drag it to the side where you can manipulate it. Use the menu or the keyboard shortcut for "Show points". A PASTED surface has control points you can access and use for manipulating the surface. I think of it as an alternative to using meshes.
(Speaking of which, are you trying to use a mix of mesh and non-mesh geometry? Using, say, a surface to modify/cut/extrude against a mesh? One reason I don't use meshes is years ago, I couldn't make surfaces extrude to meshes, and even if meshes are great, I view them as for mugs, faces, monsters, and similar. Sure, they can be used to make planes, cars, and much more, but I get stressed out doing anything with meshes, and rarely visit the mesh features.)
As a side experiment, can you create a sphere, then place two lines near it, make a surface from those two lines, and then use the split tools to split the solid sphere? Can you create a sphere and access the control points to reshape it.
Have you seen in the help manual the various tools that have similar purpose to what you want to do?
If the tools are "misbehaving", have you had any recent system or app crashes?
If none of those things work, maybe you want to reinstall the app if it's been many months last you installed it.
As far as being unable to post images, it can seem you can't but the "Attach files" check box confuses even me if I don't use it regularly. You need to attach a file, then *preview* it. Be sure to attach only supported files.
If you're too new an account or profile, there might be restrictions on attaching until you're posting new or response messages, or have read/used the forum some amount of time, but I can't remember if or how many you need to.
If you have an external, reputable repository or image site available to the public (and won't compel visitors to create accounts or ask them for passwords or privacy information), maybe put the image there and the link to in in your next forum message.
As for your installation of ViaCAD, is this on windows, or a Mac? Maybe a Mac user will be able to help.
But, again, without an image, many users may feel reluctant to get involved.
Try again to post, whether it's an image or the a ViaCAD file.
