Hello,
I have a eotech rifle optic that I modelled in plasticity. I want to bring it into blender to retopo it so it can be a subdivided. I went through through these courses, which were very helpful:
https://cgcookie.com/courses/introduction-to-retopology
https://cgcookie.com/lessons/welcome-to-the-course-fae1ef22bef06e8f
Is it possible to use mirror modifier when retopologizing with shrinkwrap on an asymmetrical object?
Here is one of the pieces of the optic that I modelled in Plasticity and brought into Blender:
Here is what it looks like from the bottom:
Is it possible to use the shrinkwrap retopo method with mirroring to recreate this as a subd model? One idea I had was to place an invisible object at the center of the symmetrical portion and mirror around that.
The other option is to just rebuild using more traditional subd modelling techniques.
My concern with using shrinkwrap retopo without mirroring is that the symmetrical parts may not be 100% accurate. Pieces of this model need to fit into other pieces, so I wouldn't want inaccuracy in my edges/etc.
If I could ask a sub question it would be: If you were given a CAD model and had to turn it into SUBD, how would you do it?
I can provide the file and/or pics of the topography if that's helpful.
Thank you for any help,
-Mike
That model is symmetrical in positive to negative Y, you can totally use the mirror modifier and model for symmetry. Same for everything else you have said, you can use traditional retopo shrink-wrap and SubD modifier. You just need to have good topology and watch those edge flows. It all applies to having a CAD model and turning it into a mesh that can be subdivided. You seem to have your approach nailed and ready to go.
Kent also goes into retopo on the HUMAN course, that can be helpful to watch. Also there is a course on using the addon Retopoflow which is what the pro's use. Linking up:
https://cgcookie.com/courses/retopology-with-retopoflow-3
https://cgcookie.com/lessons/intro-to-modeling-detailing
Thanks for the help, Omar. Glad to know I'm on the right track.
I'm going to give it a go tomorrow morning with the retopo/shrink-wrap subd modifier method. I'm guessing I should mirror +y to -y and then once I have most of it sorted out, turn off mirror modifier and extrude out that larger section that is asymmetrical on the y axis?
When I play that out in my head, the mirroring won't work on the Y axis because of the section that juts out on -y (I think it's -y that has the part that juts out). It will cause mirrored topology to be far off from the sides of the object as the center point of the object on Y is thrown off. Or does that not happen because of shrinkwrap?
And yes, I watched the retopoflow tutorial. Very cool add-on. I'm going to hold off on it for now because there's so much new stuff. A bit too overwhelming for me at the moment. I'm going to stick with the tools covered in the intro to retopology video. I'll be sure to check out the Intro to modeling detailing. Thanks for the heads up.
Thanks again for the help. I'll follow up on how it works.
Yes, you model with mirror since like 97% of the model is symmetrical, then when it comes to making that small part that has asymmetry, you apply the mirror modifier and then model that part with no mirroring. One thing I like to do is duplicate the collection before I make any destructive changes to the model and save that copy on a "Trash Bin" Collection, just in case I have to go back to the before state. Or alternatively you can just do a Save As and leave a file before you make destructive changes to the model.