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thexplosionist

Modelling issue

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Hi All,

 

 

I am trying to model a turret, and I have a concave corner that needs to be sharp . I tried what some would call a borrowed edge cut, but when applying the subdivision I encounter a little bit of a deformation on the surface as shown in the images.

 

Any idea how to go around that smoothly.

0.PNG

1.PNG

2.PNG

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Please make sure you are posting in the correct place, which is not General Discussions. Moved to Modelling.

 

The problem here is that you don't have enough topology to describe that form - look at the difference in size between your biggest and smallest polys - SDS really hates that, and deformation is almost guaranteed working this way. You need to subdivide the whole mesh, and APPLY that subdivision before you start adding details and control loops. If you upload the scene file I can show you how that would work...

 

CBR

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  • I am new here so sorry about the placement of my topic.

     

    Attached the file. I had a different approach initially (in the file) but that created different problems.

     

    Many thanks in advance.

    test.c4d

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    10 minutes ago, thexplosionist said:

    I am new here so sorry about the placement of my topic.

    Totally understandable 🙂 It's in the right place now...

     

    Thanks for uploading the file. I have to run out on some errands now before stuff closes for the day, but will look at this when I get back and show you the best way forward...

     

    CBR

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    Ok, so, let's do this...

     

    1. Remove all the control loops and 1 main edge loop, and the out-jutty bit at the bottom (and close the hole there), so you go back to what I have on the left in the pic below.

     

    image.thumb.png.ecb24e5bee92a83fc6517e98fb0a55e9.png

    2. Select the edges I have highlighted on the right, find the SDS Weighting tool, and set the weight of these edges to 100%. Put that under OpenSubDiv SDS object, level 3 in Viewport AND render. Your mesh should look like mine on the right above at this point when viewed in Isoparms mode.

     

    3. Make the SDS object editable (C) and now remove the weight tag from the model. If we switch to a wireframe mode now you will see that we have too many loops going around the object, so we need to select every other one of those and dissolve them so we retain our even polys everywhere.

     

    4. NOW is the time to pull out the (is it) heel section, so select the right polys on the bottom, and control drag them out once to create the outjut...

     

    5. Next we need to add some rather specific control loops as shown. Notice how my edge flow is redirected to go AROUND the corner of the outjut section.

     

    image.thumb.png.2396f5f9e9dfc7009ee175579f80b2c4.png

     

    6. Lastly, we can put this under Regular SDS (Catmull-Clark) , but this time Level 2, and you should get this final result, which I hope you will agree is 100% deformation free. This is possible because if you now look at that diagonal corner control loop, see the tiny distance that has to travel before it rejoins with the main flow, compared to what it had to do in your original mesh. By giving SDS what it wants to work with, it does a lovely job. BTW - phong angle should be 80 degrees at this point, so change that in the phong tag if you are getting any edge shading problems.

     

    image.thumb.png.fbdab87129f03083775cfb3c5ec1b9aa.png

     

    So that is a good way to go using SDS. But if you want much much less polys in this, you could do it with Hard Surface modelling, and bevel deformer etc...

     

    Now, we could make those edges even sharper than that if we wanted, but if we wanted them VERY sharp, then maybe SDS wasn't the way to go for this object. In that case perhaps a hard surface workflow would have been better... and it certainly would have been quicker !

     

    Hope that helps, any questions please just ask...

     

    CBR

     

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  • great .. many thanks.

     

    I thought this method was hard surface modelling . Did you mean using boolean ?

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    1 hour ago, thexplosionist said:

    I thought this method was hard surface modelling . Did you mean using boolean ?

    No. Hard surface modelling is anything using bevels instead of SDS.

     

    CBR

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  • Ah I see your point. Beveling with subdivisions to the edges. Great stuff man, many thanks.

    Where can I find your master class?

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    2 hours ago, thexplosionist said:

    Where can I find your master class?

     

    I'm afraid that's only available in personal 1-1 Skype training sessions... do PM me about those if you're interested...

     

    CBR

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