Working on a rail gun prop. Critique and advice much appreciated

Chase

I feel like I've taken another step in hard surface modeling because this is the most difficult thing I've done. However, I'm still spending too much time on blocking out the low poly. I thought I'd post what I had before I spent more time to see what everyone thinks.

Here's the reference


I know I only modeled half the circles in but other then how's my edge flow looking at the front half?





I've been working at ensuring the edge flow is even so when I slap a turbosmooth on for the high poly I can just delete unwanted edges. Is that how you'd go about it? Or just retopo the high poly? Another suggestion?

ghaztehschmexeh

Personally I do high and low separately. Sometimes you can use the high poly cage for the basis of the low poly, but not always. I generally find that the high poly cage is too low resolution to use.

Edit: Also the mesh you posted wouldn't subd very well at all. Ngons plus topology that wouldn't result in a clean mesh.

SINtuition

I have to agree with ghaztehschmexeh on both points.

The topology is not going to behave well with turbosmooth. Especially where the holes intersect with the interior curve. I might catch a few flames for suggesting this, but you might consider just booleaning out those holes from the high poly mesh since the edges of the holes are hard in the ref.

Chase

After doing some more work I ran into that problem you guys said I would run into even after fixing the Ngons. Not sure why. SIN, I did boolean the holes in and did some clean up. What's wrong with the topology that's causing my shading issues?

SINtuition

Which shading issues?

Also, I meant you should build the mesh without the holes, turbosmooth it, and then punch the holes in after the turbosmooth. Trying to keep holes perfectly round on a curved surface with turbosmooth is a nightmare.

Chase

oh snap I didn't think of that. Wouldn't cleaning up the boolean with a turbosmooth already on be even more of a nightmare? Never mind about the shading issue. I'm having trouble with this whole model. I thought it was going to be something simple but I just can't get into a groove.

ghaztehschmexeh

As SINtuition said, holes cut into a curved surface aren't easy. For example, how I cit holes cut into cylinders to make it much easier is to cut holes into a plane, subd it and then bend it. Otherwise it's a real pain to get the topo right. Obviously that won't really work here.

I suggest you have a read through the subd thread to get an idea of how to tackle the harder subd stuff. You'll probably need more geo, as currently there isn't really enough to support a curved in the holes.

Plus you're lacking support loops ;P

AlbertoLemus

The way I would approach it, would be to create a base mesh, all quads without holes, then import it into zbrush, do the holes and then use topogun to retopo. Might seem like a lot of work, but I guess that works for me.

SINtuition

Thought I'd test myself with this one. I've always had problems with this particular problem. Here's what I came up with:






TL DR!!!!

Sorry they're out of order. First off, you can see from picture 1 that there are slight imperfections in the curved surface. To be honest, I don't think you can get away with this type of mesh without SOME blips here and there.(feel free to correct me community!)

In picture 3 I show the important support loops I used to hold the curved shape. I send a single loop running vertically from the top and bottom of the knockout hole. For every other loop of the 8 sided hole I send a single loop running laterally down the length of the curved surface. This is to maintain the curvature at the rim of the holes. There is a set of radiating edges running out from the center of each hole. I found these necessary because the curved surface would stretch out long-ways at the top and bottom of the holes without them.

If you look closely at picture 4 you'll see a single loop running around the rim that is planar with the curved surface. This loop is essential. I found that no matter how many support-loops I added to the interior of the hole, I would always get this bulge in the curved surface without that one external loop. One trick to getting this loop planar with the curve is to cut it into the surface without worrying about whether its perfect. After that, turn on your edge snap in editable poly and scale it down until it's right up against the hole. Then, with edge snap still on, scale it up a bit and you'll get that loop around the rim that's planar with the curved surface.

Chase

I've been through that thread and thought I knew what to do, but clearly I'm struggling haha. I know about all the support loops and stuff. Here's what my model looks like with turbosmooth applied. The green circles are where the holes would be as more of a planning stage....





Assuming this I'm made a correct topo of my high poly where would I go from here? Ghatz, you said you create your low and high separately. How would I apply that to this mesh? I understand that you want to maintain the silhouette though I'm not entirely sure I understand where the leniency lies with having to keep the smoothness 100% or if there can be slight angularities to the shape. I'll post a picture of what I mean if that doesn't make sense haha

ghaztehschmexeh

How would I apply it? Well I'd start a new mesh and not worry about keeping all quads, and make sure it matched the surface of the high poly as closely as possibly. I'd apply a transparent texture to the high poly to make this easier (or turn on xray mode).

So yeah just match a new mesh up as closely as possible within your polycount.

Chase

Ok makes sense. Is there an easier way to rebuilding a mesh other then deleting edge loops from a turbosmooth? It would seem like you have to remember how you got the shape in the first place which could be a pain. I know I can retopo in topogun too.

ghaztehschmexeh

AFAIK topogun is more for zbrush highpolys. It shouldn't be hard to make a lowpoly, imo it's the highpoly which is the hardest.

But yeah there is no "do it for me" button.

Chase

So for the low poly I'm gonna just have to match it up closer to high poly? That's what I got out of reading Earthquake's Average Normals thread.

This is the difference in overall shape


I know you can't transfer smoothness from high to low meshes. I'll just have to had more geo to cut down the angular difference?

Chase

Progress Update

After weeks and weeks of trying to get the hole situation to work I've finally been able to sculpt. I spent about an hour putting some dents and scratches just to show some the combat usage the gun rail's been through. I'm gonna go back to work on the damage, but this was the first pass.

I used a custom brush someone else created so I want to go through the process of created my own brushes. Any scratches and cracks are placeholders.


I added surface noise using a default noise loaded in ZBrush. I want to make my own Alpha and use that for practice like the custom brushes.




Then I went to go work on the low poly to get ready for the bake. I'm not sure if I deleted enough edges. 2700 tris is a lot, especially since I don't have the rest of the model attached. I'm not even sure if I deleted the unnecessary edges correctly. I didn't want to keep going for fear I was wasting my time, but this is what I'm in the process of doing for the low poly.




If I continue down the process I have going I'm going to have a lot of triangles. Is that fine? I'm worried about the bake and whether or not I'll have issues later with the Normal Map.

Then I thought I'd try my hand at unwrapping. Ohhhh wow I'm not confident in this area what so ever. I put about 2 hours in and only have half of the model unwrapped. Most of the time was me just fighting with stitching and straightening edges for better clean up. The holes also didn't help.


How do you guys usually go about unwrapping? I feel like I was just selecting edges and hoping the selection would pelt properly or else I'd just quick planar map it. I know how to use the tools, just have no experience unwrapping anything more complicated then a box or barrel.

E_Hollaway

Im not sure I would even keep the holes in your low res model, you will run into normal and AO baking problems if you do, You can get away with just normal mapping the holes. Thats what I would do at least.

E_Hollaway

Also to answer your question about an easier way to create a low poly from a high poly, I would just retopologize the high res and just make a whole new model, 3DCoat is really good at retopo. If you leave out the holes then you can paint the holes black and play with color balance and normal depth in order to make it actually look like a hole, holes are a pain but if done correctly look amazing.

Chase

I tried what you suggested. Not being able to see through the hole is gonna be a problem only if I choose to use this as a FPS accessory. Other then that I think it turned out well...


Here's the normal map


There's a reflection going on where the hole with the normal map's applied. I'm assuming I can fix that with a spec map? Plus the shading errors, that's just ray misses?


I did a test of the bake with the holes being in both the low and high poly. It looks just as good. The holes aren't as circular, but looks ok.

Chase

I'm also going to remove the noise and the cracks, but add in a few dents and scratches. I've been told it looks like styrofoam which is not what I was going for :P