What is the reason some imported file has cracked surface?
Well , the reason could be because that is imported geometry indeed.If you transfer geometry from one cad system to another that is something like trying to translate poem or song to another language. It is possible but it is HARD to do it.
Can you highlight what you see as a 'cracked' surface? That might help narrow it down.
Did you run geometry checks on the part(s) after import? What was your import geometry format? (eg. parasolid, step, IGES, etc.)
If you mean that 'line' on the cylinder surface then that may just be the geometry interpretation from original CAD translated to import geometry.
I have shown in the above screen shot. I am not interested other than finding out the reason for the cracked surface. To try it I converted my original file into parasolid file then again converted into SWX file but I didn't get any cracked surface.
Maha Nadarasa wrote: I have shown in the above screen shot. I am not interested other than finding out the reason for the cracked surface. To try it I converted my original file into parasolid file then again converted into SWX file but I didn't get any cracked surface.
Maha Nadarasa wrote:
What crack? Can you zoom in and show detail?
..btw, ..for that Oculus Touch.. you show (GrabCad?).. it looks like it was converted from a scan/mesh/subd?.. or manipulated in Fusion360 (image/step file header)... and there is a free set of models at the Oculus developers site (image/step header.. looks like NX)
I got it from here:
How to make case for a controller?
...ok.. I just posted the developer link for Brandon..... here it is here..
Touch Accessory Guidelines | Developer Center | Oculus
This round trip from SW to Parasolid back into SW involves no mathematical translation because SolidWorks uses the Parasolid kernel. So there is no change in the body of the model. IGES, STEP, etc. are all "neutral" formats that require translation. Therefore you may from time to time get abnormalities in imported models coming from those neutral formats.
I check this with original part in my file. I purposely exported and imported this part by using parasolid file but I did not get cracked surface.
That's what Ken is telling you.
SW -> Parasolid -> SW require NO translation. So nothing is lost.
Other formats, STEP, IGES require a translation which could result in "broken" surface.
First problem from translation is ZTG. Other format allow ZTG but Parasolid doesn't.
Different use different ways to define surface.
Usual modeling features are simple. Line is a line, same with circle, arc.
Once it move to spline, you'll get problems.
This explanation followed by another question. If Parasolid does not have ZTG what is purpose of having other file conversion types(STEP, IGES).
Because we don't have a standard file sharing format.
Every CAD software use their own format.
ZTG - a point or line on a surface.
Maha Nadarasa wrote: This explanation followed by another question. If Parasolid does not have ZTG what is purpose of having other file conversion types(STEP, IGES).
..that question has some history behind it...
Geometric modeling kernel - Wikipedia
List of 3D modeling software - Wikipedia
..so, cracked is, your imported file is not stitched together, it has surface and solid bodies... or it appears broken or fragmented?
..ok (cracked = loose).. the simple explanation, each modeling system has a limit or tolerance so depending on where the data originated.. the loose boundaries may or may not stitch.
SolidWorks (parasolid) modeling accuracy (I believe?) is .000001mm (somewhat overkill imho) and it also has built in tolerance for looser (cracked) data (it allows, it's tolerant).... so, some faces come in stitched/sewn and some do not (faces).
My goto kludgy workaround for dealing with loose (cracked) data has been to export/import IGES.. this moves the data back/forth through the translators.. with a > chance for the data auto stitch.
In 2019v hard lines are appearing as a construction lines in 2020v.
Retrieving data ...