51 Chevy Pickup, COMPLETED! (For real this time!)

MonkeyT

Active member
#1
I was thinking of a painting I did when I was about 14, of an abandoned pickup in a field, and a cool photo of a 51 Chevy pickup crossed my path, so I embarked on a new project to work on modeling. I couldn't find any straight profile images to work from, so for reference, I located a good one-piece STL model (a free download). Comparing it to the photos, the curves are pretty accurate.

My version is still very incomplete, but it is created entirely using Cheetah3D's shapes, distortion modifiers and as little polygon handwork as I can manage (no splines yet). I'm very happy with the body shapes (there are lots of perspective view photos available to check against ) The front fenders were pretty challenging to plot out (and the wheel wells haven't been cut out yet) but the vent on the side was murder (it's curved vertically but with different amounts of curvature as you move upward, the surface is curved horizontally from front to back, so the vents are vertically twisted and sheared to keep the blades straight and aligned).

I also spent a good while working on the rust texture on Sunday. I've kept many files, the work files (with the modifiers and such needed to distort the shapes are still in place), and two finish files with shapes converted to polygons and assembled in place. I also have one version using the rust textures and another using showroom textures.

Suggestions are welcome.

I have only a rough strategy of how to use particles to make the model appear to be lost in the tall grass ( I could photoshop it, but I want to get as close as possible to a complete 3D render first ). Cutting out the doors and hood will also be fun.

I really do love working with this program.

51Chevy_May5.jpg
51Chevy_detail_May5.jpg

reference model:
51Chevy_reference_May5.jpg
 

MonkeyT

Active member
#4
Got a some done on details and the back half of the truck. Found a few better examples of the vent in photos - most rebuilt 51's seem to have abandoned the vent completely, and the original photos I found had fewer blades.

Have to take a break for the weekend, Sister needs to borrow my computer to do her taxes.

51 Chevy Outdoors 2.jpg
 

MonkeyT

Active member
#6
Stayed up after tax time last night.

51 Chevy Outdoors May17.jpg

Thanks again, Joel. Your grass example worked wonderfully. I see my roadmap clearly now.

I applied two different meshes to the grass plane, a green one to apply to all polygons, and a yellowish mix to match the background grasses and get some discoloration on some specifically chosen polygons in the model. I suspect I will wind up with three or four different color blends, a short mix to put under the vehicle, and very thin mix to help visually blend the far background into the HDRI. I'll also extend the grass plane deeper behind the truck. This will probably take some depth of field experimentation, too.

I think I need to try to lift the horizon of the HDRI, which probably means lowering the entire model's altitude in model space. The ground plane itself is almost transparent so I could use the HDRI's ground as texture.
 
#7
Your WIP already looks better then your reference model (that just doesn't look right with all things fused together).

About the hdri: Visually it makes more sense as it is. It looks as if your car was standing on a small hill which helps you with the contrast between your grass and the photographed grass. This border would be inexplainable for the viewer if fore- and background were on the same level.

With a bit of DOF that will look natural.
 

MonkeyT

Active member
#8
I thought about the HDRI a lot, last night. I really like the viewing angle on the truck better in the more recent image shown above, which seems more eyeball height instead of looking down on it from above it. But it does make it seem as if it's on a slight hilltop. Once I decided to let the grass be taller, this hilltop impression grew even stronger. The setting makes more sense to me as a landscape that's flat as a pancake rather than rolling hills. I've also had difficulty obscuring the edge of the 3D even with depth of field: the Falcon renderer puts a slight dithering texture on models, whereas the HDRI is rendered with a slight but very smooth blur. (This distinction shows up in the render, but it might disappear completely when the image is printed.)

DOF_falcon.jpg


With more of the flat ground exposed, I think I can accomplish more by using fewer grass particles and carefully matched colors (I've even used some spot lighting on the faraway grass to help desaturate it). For the moment, I have slightly rotated the HDRI and tweaked the angles to make certain the horizon stayed level. It's also nice to see a little bit of the far foliage color through the cab windows, though that will ultimately be seen through hard-worn (possibly broken) glass.

I will keep trying different ideas though... I may even tilt the ground plane (but not the model), which might make blending easier but be less obvious... Thanks.

51 Chevy Outdoors May19B.jpg


The newest challenge on the list is keeping the tall grass from poking through the baseboards of the truck.
 

Helmut

Well-known member
#9
* To control the grassy particle meshes and avoid interpenetration with the truck´s hardware:
* Consider using shade selections for the bases of the grass.
* I have divided the ground (a relief, made editable) into 3 such selections, grass low, grass medium and grass high which are populated with 3 different lengths of vegetation. That way you can generate a frame of grassy instances which are lower at the outer perimeter of the truck and don´t poke through fenders, mudguards and other parts.
* Shade selections in particle meshes can only be used with the types polygon and surface.

Screenshot 2020-05-20 at 08.56.54.png
 

MonkeyT

Active member
#10
That's actually my first guess! I'm already using this feature to mix different grass colors, and have considered making a mix of short, darker grass specifically to go under the truck. I'll have to re-shuffle the current assignments a little because the tall yellow grasses are currently set to "all" while the two different green grass mixes are assigned to 0 and 1.

Thanks!
 

Helmut

Well-known member
#11
* Don´t forget that a particle mesh can have >1 components.
* So, you can have a mesh with grass A (tall & yellow), grass B (green #1), grass C (green #2) and mushrooms with polka dots. Fiddling with particle order and seed may get you there.
 

Helmut

Well-known member
#13
:unsure: Not sure that I understand the question. Please elaborate.
:sick: I don't know what you refer to as proportions.
* The particle order does not change the randomness, it will simply swap instances when populating the mesh. So, if you exchange grass-yellow to grass-green in the particle mesh, the locations will remain static, but where you had grass-green you now have grass-yellow and vice versa.
 

MonkeyT

Active member
#14
Elaboration: comparing the total number of rendered components A, B and C assigned to a single mesh. Does A consistently get a higher number of instances than B, which is higher than C, or are all quantities equal - OR (as your response seems to indicate) those quantities and their positions are determined randomly according to the seed value, but changing the sequence of the components swaps which component gets rendered in those already-chosen positions.

I'm pretty sure you did answer the question I asked. Thanks
 

Helmut

Well-known member
#15
* As far as I know, the instances should be numerically equal (provided there is an integer division by 3 / or whatever). I may have never counted them, but there has been no blatant discrepancy in my use of partricle engines.

* Maybe useful as well:
* A particle mesh can not only deal with a flat hierarchy (all nodes on the same level), you can also use a hierarchy proper (parental node + indented children).
* In this case every instantiation will be a cluster of n objects (eg, green grass / parent + yellow grass / child #1 + a rainworm / child #2).

Greetings to Texas from Vienna
:rolleyes: I do remember some of the old songs by Boz Szaggs
 

MonkeyT

Active member
#16
Getting close to the finish line. Did lots of work on the grasses, added a windshield, and tweaked the bumper rust texture. Reworked the hood badge to something more authentic, too - when I tried to execute the boolean subtraction of the letters from the badge object that was built and shaped with modifiers, it freaked out. I had to convert the shape to polygons first and then subtract the letters through several steps.

51 Chevy Outdoors May23.jpg


The doors need triangular vent windows, there's another badge on the side, and I still have to cut out the doors and hood from the body form. Still having a little trouble with grass poking through the front bumper - will work on this tomorrow - and I want the windshield just a little more transparent (That's actually a simple solid shape with a funky texture.) I may weaken the depth of field effect just a little more... It's starting to give off a toy car impression...

Any other suggestions before I wrap it up?
 

MonkeyT

Active member
#17
Pretty much all but the cutting is done. It turns out the fender and the body have a smithed edge between them, so I merged the two parts and manually softened the join before cutting the hood. I put together a proof to hammer out how to cut it cleanly, and it worked (even though it was cranky) but I mis-measured the depth of the cut in front and will need to execute it again. Then, all that is left is to cut the door and add a few details to it and the sideboard. I've also finally located a photo which shows what's obscured behind the grill - originally, you could barely see an opening for the radiator, but some rebuilds close the space off entirely. There's also another pair of lights buried behind the grill very often, but they don't stand out very much.

51 Chevy Outdoors May24.jpg
 

Helmut

Well-known member
#20
* Excellent work :oops::rolleyes::whistle:
* Looks like somebody cleans the windows regularly, wipes off bird poo and and removes weeds growing from cracks in the body work.
* As does Doc Martin, I quite like these mediaeval Baroque automotive designs embellished with a veneer of antique industrial cyberpunk. Great stuff!
 
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